A. No obligation to forgive unrepentant brethren:

LUK 17:3. Take heed to yourselves: If thy brother trespass against thee, rebuke him; and if he repent, forgive him.

MAT 18:15. Moreover if thy brother shall trespass against thee, go and tell him his fault between thee and him alone: if he shall hear thee, thou hast gained thy brother.

ROM 16:17. Now I beseech you, brethren, mark them which cause divisions and offences contrary to the doctrine which ye have learned; and avoid them.

1COR 5:11. But now I have written unto you not to keep company, if any man that is called a brother be a fornicator, or covetous, or an idolater, or a railer, or a drunkard, or an extortioner; with such an one no not to eat.

1COR 5:13. But them that are without God judgeth. Therefore put away from among yourselves that wicked person.

2TH 3:6. Now we command you, brethren, in the name of our Lord Jesus Christ, that ye withdraw yourselves from every brother that walketh disorderly, and not after the tradition which he received of us.

2TH 3:14. And if any man obey not our word by this epistle, note that man, and have no company with him, that he may be ashamed.

TIT 3:10. A man that is an heretick after the first and second admonition reject;

2JO 1:10. If there come any unto you, and bring not this doctrine, receive him not into your house, neither bid him God speed:

2JO 1:11. For he that biddeth him God speed is partaker of his evil deeds.

B. There is a time to be firm:

1COR 4:18. Now some are puffed up, as though I would not come to you.

1COR 4:21. What will ye? shall I come unto you with a rod, or in love, and in the spirit of meekness?

TIT 1:13. This witness is true. Wherefore rebuke them sharply, that they may be sound in the faith;

C. Show mercy & patience in order to help them repent & do not pardon them until they do:

LUK 13:6. He spake also this parable; A certain man had a fig tree planted in his vineyard; and he came and sought fruit thereon, and found none.

LUK 13:7. Then said he unto the dresser of his vineyard, Behold, these three years I come seeking fruit on this fig tree, and find none: cut it down; why cumbereth it the ground?

LUK 13:8. And he answering said unto him, Lord, let it alone this year also, till I shall dig about it, and dung it:

LUK 13:9. And if it bear fruit, well: and if not, then after that thou shalt cut it down.

ROM 2:3. And thinkest thou this, O man, that judgest them which do such things, and doest the same, that thou shalt escape the judgment of God?

ROM 2:4. Or despisest thou the riches of his goodness and forbearance and longsuffering; not knowing that the goodness of God leadeth thee to repentance?

ROM 2:5. But after thy hardness and impenitent heart treasurest up unto thyself wrath against the day of wrath and revelation of the righteous judgment of God;

ROM 2:6. Who will render to every man according to his deeds:

GAL 6:1. Brethren, if a man be overtaken in a fault, ye which are spiritual, restore such an one in the spirit of meekness; considering thyself, lest thou also be tempted.

D. Serious offenders must change not merely be sorry:

ISA 55:7. Let the wicked forsake his way, and the unrighteous man his thoughts: and let him return unto the LORD, and he will have mercy upon him; and to our God, for he will abundantly pardon.

MAT 3:8. Bring forth therefore fruits meet for repentance:

MAT 3:10. And now also the axe is laid unto the root of the trees: therefore every tree which bringeth not forth good fruit is hewn down, and cast into the fire.

MAT 7:19. Every tree that bringeth not forth good fruit is hewn down, and cast into the fire.

LUK 3:8. Bring forth therefore fruits worthy of repentance, and begin not to say within yourselves, We have Abraham to our father: for I say unto you, That God is able of these stones to raise up children unto Abraham.

LUK 3:9. And now also the axe is laid unto the root of the trees: every tree therefore which bringeth not forth good fruit is hewn down, and cast into the fire.

PSA 51:10. Create in me a clean heart, O God; and renew a right spirit within me.

PSA 101:3. I will set no wicked thing before mine eyes: I hate the work of them that turn aside; it shall not cleave to me.

JER 3:10. And yet for all this her treacherous sister Judah hath not turned unto me with her whole heart, but feignedly, saith the LORD.

HOS 6:4. O Ephraim, what shall I do unto thee? O Judah, what shall I do unto thee? for your goodness is as a morning cloud, and as the early dew it goeth away.

E. They must confess their sin & ask for forgiveness:

PSA 32:5. I acknowledge my sin unto thee, and mine iniquity have I not hid. I said, I will confess my transgressions unto the LORD; and thou forgavest the iniquity of my sin. Selah.

PSA 86:5. For thou, Lord, art good, and ready to forgive; and plenteous in mercy unto all them that call upon thee.

ACT 3:19. Repent ye therefore, and be converted, that your sins may be blotted out, when the times of refreshing shall come from the presence of the Lord.

1JOH 1:9. If we confess our sins, he is faithful and just to forgive us our sins, and to cleanse us from all unrighteousness.

2COR 2:6. Sufficient to such a man is this punishment, which was inflicted of many.

2COR 2:7. So that contrariwise ye ought rather to forgive him, and comfort him, lest perhaps such a one should be swallowed up with overmuch sorrow.

2COR 2:8. Wherefore I beseech you that ye would confirm your love toward him.

F. Don't use this as an excuse to be unforgiving:

MAT 5:22. But I say unto you, That whosoever is angry with his brother without a cause shall be in danger of the judgment: and whosoever shall say to his brother, Raca, shall be in danger of the council: but whosoever shall say, Thou fool, shall be in danger of hell fire.

G. God still loves the wayward & you should too:

PSA 89:30. If his children forsake my law, and walk not in my judgments;

PSA 89:31. If they break my statutes, and keep not my commandments;

PSA 89:32. Then will I visit their transgression with the rod, and their iniquity with stripes.

PSA 89:33. Nevertheless my lovingkindness will I not utterly take from him, nor suffer my faithfulness to fail.

2TH 3:15. Yet count him not as an enemy, but admonish him as a brother.

JAM 5:19. Brethren, if any of you do err from the truth, and one convert him;

JAM 5:20. Let him know, that he which converteth the sinner from the error of his way shall save a soul from death, and shall hide a multitude of sins

H. When they repent He will love them freely:

HOS 14:4. I will heal their backsliding, I will love them freely: for mine anger is turned away from him.

Special chapters:

1COR 13:1. Though I speak with the tongues of men and of angels, and have not charity, I am become as sounding brass, or a tinkling cymbal.

1COR 13:2. And though I have the gift of prophecy, and understand all mysteries, and all knowledge; and though I have all faith, so that I could remove mountains, and have not charity, I am nothing.

1COR 13:3. And though I bestow all my goods to feed the poor, and though I give my body to be burned, and have not charity, it profiteth me nothing.

1COR 13:4. Charity suffereth long, and is kind; charity envieth not; charity vaunteth not itself, is not puffed up,

1COR 13:5. Doth not behave itself unseemly, seeketh not her own, is not easily provoked, thinketh no evil;

1COR 13:6. Rejoiceth not in iniquity, but rejoiceth in the truth;

1COR 13:7. Beareth all things, believeth all things, hopeth all things, endureth all things.

1COR 13:8. Charity never faileth: but whether there be prophecies, they shall fail; whether there be tongues, they shall cease; whether there be knowledge, it shall vanish away.

1COR 13:9. For we know in part, and we prophesy in part.

1COR 13:10. But when that which is perfect is come, then that which is in part shall be done away.

1COR 13:11. When I was a child, I spake as a child, I understood as a child, I thought as a child: but when I became a man, I put away childish things.

1COR 13:12. For now we see through a glass, darkly; but then face to face: now I know in part; but then shall I know even as also I am known.

1COR 13:13. And now abideth faith, hope, charity, these three; but the greatest of these is charity.

1JOH 1:1. That which was from the beginning, which we have heard, which we have seen with our eyes, which we have looked upon, and our hands have handled, of the Word of life;

1JOH 1:2. (For the life was manifested, and we have seen it, and bear witness, and shew unto you that eternal life, which was with the Father, and was manifested unto us;)

1JOH 1:3. That which we have seen and heard declare we unto you, that ye also may have fellowship with us: and truly our fellowship is with the Father, and with his Son Jesus Christ.

1JOH 1:4. And these things write we unto you, that your joy may be full.

1JOH 1:5. This then is the message which we have heard of him, and declare unto you, that God is light, and in him is no darkness at all.

1JOH 1:6. If we say that we have fellowship with him, and walk in darkness, we lie, and do not the truth:

1JOH 1:7. But if we walk in the light, as he is in the light, we have fellowship one with another, and the blood of Jesus Christ his Son cleanseth us from all sin.

1JOH 1:8. If we say that we have no sin, we deceive ourselves, and the truth is not in us.

1JOH 1:9. If we confess our sins, he is faithful and just to forgive us our sins, and to cleanse us from all unrighteousness.