Matthew 18:21

Then Peter came and said to Jesus, "Lord, how often must I forgive my brother when he sins against me? As many as seven times?"

Luke 17:3-4

Pay attention to yourselves! "If your brother sins, rebuke him [i.e., show him where he is wrong in hope of effecting a change]; and if he repents [i.e., changes his heart and life], forgive him.

Matthew 18:15

"And if your brother sins against you, go and show him where he wronged you, [but] keep it between just the two of you. If he listens to you [i.e., accepts your reasoning and repents], you have won your brother [back].

Treasury of Scripture Knowledge

Summary

Then came Peter to him, and said, Lord, how oft shall my brother sin against me, and I forgive him? till seven times?

Bible References

Till

Matthew 18:15
"And if your brother sins against you, go and show him where he wronged you, [but] keep it between just the two of you. If he listens to you [i.e., accepts your reasoning and repents], you have won your brother [back].
Luke 17:3
Pay attention to yourselves! "If your brother sins, rebuke him [i.e., show him where he is wrong in hope of effecting a change]; and if he repents [i.e., changes his heart and life], forgive him.