Matthew 18:15 (CSB) "If your brother sins against you, go and rebuke him in private. If he listens to you, you have won your brother.

Rebuke, today we don't like that word. It sounds harsh it sounds mean, but it should not be it should be out of love (Revelation 3:19). We should want our brothers and sisters In Christ to better their life. A rebuke can do this. 2 Timothy 3:16 says the word of God is useful for rebuke. Through prayer and concern for our fellow Christian we can take them the Word of God to shine a light into the sin in their life. The Holy Spirit may move upon you to prophecy to another person that their current course of life will lead to despair (1 Corinthians 14:3). It would be best to first tell this person in private, one on one. I heard a military person say one time, rebuke in private, and praise in public." A rebuke is hard enough to take without a bunch of other people hearing it.

Psalm 141:5 (CSB)
Let the righteous one strike me --it is an act of faithful love; let him rebuke me --it is oil for my head; let me not refuse it. Even now my prayer is against the evil acts of the wicked.