Writing status: This is a little out-of-hand and probably raises
some questions I'm not aware of.
The moral circle is the set of all beings to which we consider 
ourselves to have moral obligations.  Something can be inside, or outside,
one's moral circle, a member, or not, of the set of beings to which we
consider ourselves to have moral obligations.  The reason for 
why something belongs in the moral circle is because it has feelings, 
especially that it suffers, in such a way that we need to respond to its 
circumstances.  Generally, we need to respond when something threatens
a feeling being's well-being.  (This is how "moral circle" is generally 
used, and that is how I'll be using the concept in this post.  
Conceivably, we could have moral obligations for other reasons.)
  
As we come to really take into account the existence of feeling beings, 
we include them in our moral circle.  So for instance, we might consider 
that the impairment of well-being that happens in distant countries of people 
we will never know personally is just as bad as that which happens to us 
or to people we care about personally, in our own lives.  Therefore, if 
we are morally obligated to help the people in our own lives, we should 
help the people far away if we can, all things being equal.
A Christian could counter-argue that righteousness comes by faith,
and that the point of the gospel is that it is not you who save yourself
by your works, but rather God who saves you by his grace.  It could be argued
that to a Christian, moral obligation does not exist.  We live in the
freedom of being covered by Jesus' blood, shed on the cross.
Is it really Christian to say "I don't have to worry about anything
in secular ethics.  I don't rely on reason.  I rely on grace.  I am
OK."?
It may be the case that salvation is only by grace, apart from works.
I think this is an area that is nuanced.  Perhaps forgiveness of sins
is by grace, but repentance is up to us.  I think that makes sense,
and maybe I will find that the Bible supports it, when I do another 
study of the Bible to check against the religious philosophy I've been 
working on.  I think something like that is what the 
New Wine System teaches, according 
to its developer.
But I will grant for the sake of argument that perhaps grace saves,
and "saves" means "does everything that it takes to give a person eternal life".
In that case, if your only concern is salvation, then great.  As soon
as you do whatever it is you need to in order to receive that grace
(or even, nothing at all, if that's all that's required), then 
you can live your life as you please.  You can be as moral as you feel like,
and no more moral than is reasonable, in your eyes.
You certainly care about your own well-being.  You are covered by
grace, and have received the gift of salvation, in which you rest.  But 
do you love God?  Do you have the same heart as he has for people?  Can 
you love someone without caring about what they care about?  If you're 
the kind of person who only cares about your own salvation, do you think 
God is pleased with you?  Do you think God can leave you in that state?  
So God will eventually teach you to care like he does.  If grace saves,
then you were always saved.  But God will make you care like he does.
Does God love you?  Does he love people far away?  If he loves you,
why not people far away?  Are you better than them, more deserving of
a life of comfort and wealth than they are?  It's true that there is 
some nuance to this.  The material wealth of the West isn't all it's
cracked up to be.  Material wealth doesn't always make life better.  
And a certain amount of impaired well-being is an acceptable part of life.  
But some people suffer so much for being poor that there isn't really that 
much nuance in their case.  Suffering itself beyond a certain threshold
is impaired well-being, and God suffers with their suffering, just as 
he does with yours.  If you can alleviate your own suffering, you tend 
to do that.  So why not alleviate others' suffering?  You love God by 
alleviating your own suffering, and you love him by alleviating
that of distant people.  This is the love of a healer healing, or a
servant washing someone's feet.
So far, I haven't brought up the Bible.  I can't provide a rigorous
survey right now of the Bible's teachings on economic sin.  But I can
give some basic thoughts that are suggestive.  In general, I know that
many references to caring for the poor can be found in the Bible.
The Old Testament prophets talked about that.  Also in the New Testament,
James speaks strongly against people who hold onto their wealth,
causing the deprivation of those who work for them.  One could say that
James is no better than Paul, who says "salvation is by grace through
faith, apart from works", but then, is Paul any better than James?
I don't think that "salvation is by grace through works" means "we 
don't need to do the right thing" (not even Paul believed that), but
if "grace" is taken to mean "we don't need to do works", then
supposing that we need the words of Jesus to settle the dispute we might
see between James and Paul, what does he say?
Luke 10:
25 Behold, a certain lawyer stood up and tested him, saying, "Teacher, 
what shall I do to inherit eternal life?"
26 He said to him, "What is written in the law? How do you read it?"
27 He answered, "You shall love the Lord your God with all your heart, 
with all your soul, with all your strength, and with all your mind; and 
your neighbor as yourself."
28 He said to him, "You have answered correctly. Do this, and you will 
live."
29 But he, desiring to justify himself, asked Jesus, "Who is my 
neighbor?"
30 Jesus answered, "A certain man was going down from Jerusalem to 
Jericho, and he fell among robbers, who both stripped him and beat him, 
and departed, leaving him half dead. 31  By chance a certain priest was 
going down that way. When he saw him, he passed by on the other side. 
32  In the same way a Levite also, when he came to the place and saw 
him, passed by on the other side. 33  But a certain Samaritan, as he 
traveled, came where he was. When he saw him, he was moved with 
compassion, 34  came to him, and bound up his wounds, pouring on oil 
and wine. He set him on his own animal, brought him to an inn, and 
took care of him. 35  On the next day, when he departed, he took out 
two denarii, gave them to the host, and said to him, 'Take care of him. 
Whatever you spend beyond that, I will repay you when I return.' 36  
Now which of these three do you think seemed to be a neighbor to him 
who fell among the robbers?"
37 He said, "He who showed mercy on him."
Then Jesus said to him, "Go and do likewise."
The people in Jesus' audience in 1st-century Palestine couldn't 
have been held accountable for people in the New World, and perhaps 
not for people in China.  But nowadays, we can encounter people who 
are distant from us.  We hear that they are metaphorically lying by 
the side of the road, and we can choose to be neighbors to them, or 
not.  Do we want to do what Jesus said?  Do we care what he thinks 
and feels?  You could argue that technically, the priest and the 
Levite could have inherited eternal life, because the man by the 
side of the road was someone they didn't have to be a neighbor to, so 
he wasn't.  But if we are to love God with all our beings, as Jesus 
and the lawyer agreed were the way to eternal life, then we have to 
be interested in what Jesus wanted.
It's interesting to note that the lawyer thinks (and Jesus 
doesn't contradict) that to do good to someone is to show mercy
to them.  Altruism can have different psychological fuels, like
how you can have a gas stove, or a wood stove, which itself can
burn different kinds of wood.  If we have mercy, when we recognize 
that the people around us do not love like Jesus wanted us to love, 
and that we do not either, we do not judge.
  
At the same time, if we want eternal life, we need to love God 
and love our neighbors as ourselves.  These commands are ones that 
we ourselves can keep, if we have time.  So the New Wine System 
teaches that we have time in which to learn after death, before we are brought before 
God to be with him forever.  Someday we must become the kind of 
people who really do have the heart of God.
 
Some might say things changed at the cross, though.  Maybe much 
of Jesus' teaching can be set aside, since he taught it to people 
before his death.  Once he died, his death covers our sins, so we 
no longer need to take his living words as literally.  How much 
actually changed at the cross, though?  Consider these two passages 
from Matthew:
Matthew 5 (Jesus speaking):
17  "Don't think that I came to destroy the law or the prophets. 
I didn't come to destroy, but to fulfill. 18  For most certainly, I 
tell you, until heaven and earth pass away, not even one smallest 
letter or one tiny pen stroke shall in any way pass away from the 
law, until all things are accomplished. 19  Therefore, whoever 
shall break one of these least commandments and teach others to do 
so, shall be called least in the Kingdom of Heaven; but whoever 
shall do and teach them shall be called great in the Kingdom of 
Heaven. 20  For I tell you that unless your righteousness exceeds 
that of the scribes and Pharisees, there is no way you will enter 
into the Kingdom of Heaven."
And Matthew 22:
34 But the Pharisees, when they heard that he had silenced the 
Sadducees, gathered themselves together. 35 One of them, a lawyer, 
asked him a question, testing him. 36 "Teacher, which is the 
greatest commandment in the law?"
37 Jesus said to him, "'You shall love the Lord your God with 
all your heart, with all your soul, and with all your mind.'" 38  
This is the first and great commandment. 39  A second likewise is 
this, 'You shall love your neighbor as yourself.' 40  The whole 
law and the prophets depend on these two commandments."
 
Jesus says, in Matthew 5, that there is a law that lasts until
heaven and earth pass away (which means, we are still under it).
Is this the law of Moses?  Or is this the law of loving God with
all your being, and your neighbor as yourself?  This might be
hinted by the Matthew 22 quote.  Or is it some other
law?
  
It seems like another candidate might be "profess to be a 
Christian and approve of the people in your life".  Grace says
"You aren't any better than anybody else -- you need grace -- so 
approve of other people.  And faith is how you're saved -- just 
think that you trust God, and you do."  That sort of sounds like 
it's a subset of "love God with all your being and love your 
neighbor as yourself".  Certainly disapproving of people can hurt 
people sometimes.
  
Note that the "profess and approve" (arguably 
grace-and-faith-based) formula does fairly well with leading you
to love your neighbor as yourself, but not as well with leading
you to love God with all your being.  The profession is only a 
beginning compared to loving God with all your being.
  
Because "profess and approve" is easier, it's popular, and the kind
of thing people like to believe.  It's an easy way to get people
to like you.  Just say "Let's go easy on each other and ourselves 
and approve of each other, professing faith in God", and you are 
more likely to make friends than if, among your prosocial "love 
your neighbor as yourself" (which might win you some popularity 
points, since it causes you to benefit people), you also say "love 
God with all your being".  "Profess and approve" is a version of 
Christianity that the universal 
culture would select for.  (To the extent that "love God with 
all your being and your neighbor as yourself" is popular and selected
for, it tends to downplay loving God in any way that threatens
to take away from human well-being, and so it tends to be a 
different flavor of the same appealing-to-humans thing.)
  
But the law that lasts to the end of heaven and earth that is
actually offered by Jesus might be "love God with all your being
and love your neighbor as yourself", but he did not set up the
"profess and approve" law (or the "love God with all your being
which means nothing other than loving your neighbor a lot" law).  
He didn't want us to judge, and yet he himself did not approve of 
everyone and everything.  He told people he was being kind to to 
stop sinning.  Professing allegiance to Jesus certainly counts 
for something, and something like approving of other people (not 
judging them, as Jesus commanded) also counts for something, 
and they could be considered part of the "love God with all your 
being and your neighbor as yourself" law.  They are an entry 
point to the bigger and fuller law of love.  (And so can the 
"love people" laws that are used as substitutes for "love God
with all your being and love your neighbor as yourself".)
--
Many people, among those who "profess and approve" and those
who "love people", if asked, would identify as those who love
God.  If we identify as those who love God, then why shouldn't we care
about how he feels about his other children?  To live up to our calling
as lovers of God -- as children of God -- we should care about 
people who live far away from us.  There are practical limitations
to our ability to help people far away, but they are not absolute,
and within them we should do something.
However, is this exactly the same thing as "expanding the moral
circle" in a secular sense?  Is this really moral obligation, and is
this something done as a response to the impaired well-being of 
another feeling being?  In Jesus' parable of the Samaritan helping 
someone he runs into on the side of the road, the action taken is 
definitely in response to the injury of a feeling being.
As to moral obligation, if we want eternal life, we must obey God's 
commands to love.  You could look at that as moral obligation -- 
"we must" -- or not -- "we must only if we want eternal life and" 
-- presumably -- "we want God's approval" -- he set up the incentive 
to make things be the way he wanted them.  But God's approval is the 
approval of legitimacy itself, and what is required to satisfy 
legitimacy is morally obliged, since morality is what legitimacy wants.
We find ourselves unwilling to say "thus says God" 
in moral areas (rely on God's commands to love as the foundation of 
moral obligation) and tend to rely on secular morality instead.  Maybe 
it sounds overbearing to bring God into the picture.  So instead we 
rely on the secular psychology of morality that relies on instinct 
and social pressure to produce feelings of moral obligation.  But 
with God as the basis of moral obligation, there can be such a thing 
as realistic absolute standards 
-- grace allowing for the attainment of uncompromising holiness.  
Whereas, godless morality throws out wild absolutes with no way to 
live up to them -- so people become moral anti-realists.  God, who is 
legitimacy itself (/himself), the truth, 
requires us to be aligned with him -- being aligned with legitimacy is 
itself to have fulfilled moral obligation.  So I think we are
morally obligated due to other's impaired well-being, but that moral 
obligation doesn't work the same in the context of God, as in the 
context of godlessness.
--
What about non-human animals?  Extending the moral circle to non-human
animals makes sense from a secular perspective.  Materialists tend to want
to do that, because animal brains aren't sufficiently different from ours
in most (or all?) cases for us to think that they don't suffer consciously.  
From an immaterialist standpoint, we may think that animal bodies that
appear before us only appear to have consciousnesses (similarly, we may 
think that other people are only p-zombies).  But ordinaristically, we see that people are conscious and so 
are non-human animals.  Even if we are sticklers for immaterialist ontology, 
ignoring the ordinary, we should have uncertainty that non-human animal 
bodies do not have animal consciousnesses associated with them, in the way 
that each of our own bodies are associated with each of our consciousnesses.  
This uncertainty should keep us from disregarding them as feeling beings.
Similarly, it makes sense to have some sense of uncertainty that
artificial intelligences that behave sufficiently like humans are not
conscious.
But what does the Bible say?  There's nothing in the Bible about
artificial intelligences, unless you expand what you mean by that to
include organizations and states, which do not seem to be regarded
as having personhood in a literal sense (although they can in a symbolic
sense, as in prophecy).  As to animals, again, this is not an exhaustive
survey, but in Jonah 4, it says:
10 Yahweh said, "You have been concerned for the vine, for which you 
have not labored, neither made it grow; which came up in a night and 
perished in a night. 11 Shouldn't I be concerned for Nineveh, that 
great city, in which are more than one hundred twenty thousand persons 
who can't discern between their right hand and their left hand, and 
also many animals?"
This lends some weight to the thought that God cares about animals.
From Jesus (Matthew 10):
29  "Aren't two sparrows sold for an assarion coin?  Not one of them 
falls to the ground apart from your Father's will. 30  But the very 
hairs of your head are all numbered. 31  Therefore don't be afraid. You 
are of more value than many sparrows."
God cares more about humans, but vs. 31 wouldn't be as reassuring if
we thought that God didn't care about the value of sparrows at all.
Why might God care about animals, but not as much as about humans?
I'm not really sure.  One possibility is that humans are sons and daughters
of God, while animals are no more nor less than animals.  God is more akin 
to us than he is to animals (the Bible says that we are made in his
image, but does not say this of non-human animals).
I have thought before 
that animals may be persons -- do I think they are persons in the 
full-fledged sense that we are?  In the sense that we say "I think, 
therefore I am", the way that we know ourselves as people, the full 
meaning behind the "I" that we speak there?  Or are they only persons 
in the sense that they are consciousnesses with wills and preferences?  
Is there a difference between the latter and the former?  If there is, 
then animals can still suffer, trust and have their preferences thwarted, 
and yet not be full persons.
  
Animals may not have free will in the same 
way that we do, at least to the extent of not being capable of moral 
reasoning, and thus are not capable of really loving God, really choosing 
him, or any other being, for that matter.  When animals love, they have 
no choice, perhaps.  It is also possible to look at lives and persons as
different in terms of valuing them.  So it's valuable to God
to make animal lives go well (e.g., not be unremitting suffering), 
but animals themselves, as persons or proto-persons, are not as 
valuable.  (The contents of these last two paragraphs are speculations 
that I may revisit later.)
From all this, I feel somewhat safe saying that the Bible supports
eliminating gratuitous animal suffering, such as that caused by factory
farming or cruelty to animals.  We have enough uncertainty about whether
God cares about animal suffering (importantly, it's hard for us to rule
out that his care does not include caring about their suffering) that in
cases where we don't really need to cause animal suffering, we shouldn't.
  
--
Finally, it is important for Christians to include God in their
moral circle.  This is part of loving God with all our being.  God
has well-being.  The Scriptures say that he has emotions, which have
been negative in response to events on earth, and our time is no 
exception.  So we have a reason to care about him, in himself.  But 
we tend to forget this.
  
One possible reason for this is that among 
Christians there are two opposing ideas (or ideas like one or the other
of them): one, that we should adjust ourselves to fit God because he 
is perfect (and he is perfect according to a human idea of what 
perfection is -- he is all-great and thus can't have any kind of need 
by which we could benefit him); and the other, that God exists primarily 
to serve human well-being, or that human well-being was always truly 
what God wanted (and well-being is to be understood according to a 
human understanding of well-being), therefore we have no need to 
inquire into God's well-being, since God's well-being, if it exists, 
is identical with ours as we understand it (and perhaps we would also 
want to include the rest of creation to be considered with us -- 
plants, and animals, and so on).  We can see the influence of these 
two ideas, or ideas like them, in various parts of Christianity, and 
perhaps there are not so many who are free from both of them.
If God is part of our moral circle, we might have to change to adjust 
to that fact, just as how the 
inclusion 
of distant people into our moral circle can change our lives.