DNB,
Okay, lets see what we can explore;
[1] are we our brothers keeper?
Yes]
Anyone who is a Christian for any amount of time should know what Kingdom living implies for people we come into contact with.
[2] in what way are we?
We are to treat them as ourselves, preserve their well-being, as much as we are able.]
Exodus 23:4-5
23:4. "If you meet your enemy's ox or his donkey wandering away, you shall surely return it to him.
5. "If you see the donkey of one who hates you lying helpless under its load, you shall refrain from leaving it to him, you shall surely release it with him.
Leviticus 19:16-17
19:16. "'Do not go about spreading slander among your people. "'Do not do anything that endangers your neighbor's life. I am the LORD. 17. "'Do not hate your brother in your heart. Rebuke your neighbor frankly so you will not share in his guilt.
Deuteronomy 22:1-4
22:1. "You shall not see your countryman's ox or his sheep straying away, and pay no attention to them; you shall certainly bring them back to your countryman.
2. "If your countryman is not near you, or if you do not know him, then you shall bring it home to your house, and it shall remain with you until your countryman looks for it; then you shall restore it to him.
3. "Thus you shall do with his donkey, and you shall do the same with his garment, and you shall do likewise with anything lost by your countryman, which he has lost and you have found. You are not allowed to neglect them.
4. "You shall not see your countryman's donkey or his ox fallen down on the way, and pay no attention to them; you shall certainly help him to raise them up.
Ezekiel 3:18-18
3:18. "When I say to the wicked, 'You will surely die,' and you do not warn him or speak out to warn the wicked from his wicked way that he may live, that wicked man shall die in his iniquity, but his blood I will require at your hand.]
Yes all good sections of scripture about helping out others, except that Leviticus verse that could indicate the tares among the wheat?
Leviticus 19:16-17
19:16. "'Do not go about spreading slander among your people.
"'Do not do anything that endangers your neighbor's life. I am the LORD.
17. "'Do not hate your brother in your heart.
Rebuke your neighbor frankly so you will not share in his guilt.
Can you imagine, or perhaps you have encountered certain disturbed persons, who out of jealousy or envy, seek to undermine a fellow professed Christian???
They slander the person in public, this shows they hate them in their heart.
we are to rebuke them frankly....
Paul experienced such persons; 2 cor.11
25 Thrice was I beaten with rods, once was I stoned, thrice I suffered shipwreck, a night and a day I have been in the deep;
26 In journeyings often, in perils of waters, in perils of robbers, in perils by mine own countrymen, in perils by the heathen, in perils in the city, in perils in the wilderness, in perils in the sea, in perils among false brethren;
False brethren are obsessed with their own self-righteousness, gripped by envy and bitterness they stalk real Christians, try to slander and bear false witness against them, in an effort to make themselves appear to be "more spiritual" by trying to put the real Christian down.
They imagine they are being spiritual, or keeping up a facade for some odd perverse reason by engaging in such evil works.
[3] is this a duty or an option?
There are both sins of commission, and sins of omission.
4] how much or to what extent do we do this?
As long as they are warned, as long as you did all that you could to assist]
Yes;
Gal6;
9 And let us not be weary in well doing: for in due season we shall reap, if we faint not.
10 As we have therefore opportunity, let us do good unto all men, especially unto them who are of the household of faith.
[5]are there any boundaries to this?
Until it does more damage than good.]
Yes, sadly we must withdraw from such persons sometimes,
17 Now I beseech you, brethren, mark them which cause divisions and offences contrary to the doctrine which ye have learned; and avoid them.
18 For they that are such serve not our Lord Jesus Christ, but their own belly; and by good words and fair speeches deceive the hearts of the simple.
19 For your obedience is come abroad unto all men. I am glad therefore on your behalf: but yet I would have you wise unto that which is good, and simple concerning evil.
20 And the God of peace shall bruise Satan under your feet shortly. The grace of our Lord Jesus Christ be with you. Amen.
[6] do we risk losing fellowship over this issue?
Yes. Some may resent you for calling them sinners, or assuming that they need help or want it.]
They behave opposite than the wise person would;
16 These six things doth the Lord hate: yea, seven are an abomination unto him:
17 A proud look, a lying tongue, and hands that shed innocent blood,
18 An heart that deviseth wicked imaginations, feet that be swift in running to mischief,
19 A false witness that speaketh lies, and he that soweth discord among brethren.