Always deal with another person in grace. Understand and operate on the principle of grace. This does not compromise your convictions. Forgive as the Lord Jesus Christ forgave - completely and immediately. Rom. 7:14-15.
“For we know that the Law is spiritual, but I am of flesh, sold into bondage to sin. For what I am doing, I do not understand; for I am not practicing what I would like to do, but I am doing the very thing I hate.” (Romans 7:14-15, NASB)
You must maintain an attitude of fellowship toward other believers who may be out of fellowship. James 5:19-20.
“My brethren, if any among you strays from the truth and one turns him back, let him know that he who turns a sinner from the error of his way will save his soul from death and will cover a multitude of sins.” (James 5:19-20, NASB)
Our Lord’s washing of His disciples feet in John 13:2-20 speaks of restoration to fellowship, rather than getting saved.
“Then He poured water into the basin, and began to wash the disciples' feet and to wipe them with the towel with which He was girded.” (John 13:5, NASB)
“"Truly, truly, I say to you, he who receives whomever I send receives Me; and he who receives Me receives Him who sent Me."” (John 13:20, NASB)
The context teaches that one is saved once and for all, but needs many restorations to fellowship. The analogy is that the bath (washing the whole body) speaks of salvation, whereas the washing of feet done many times refers to getting back into fellowship. 1 John 1:9.
“If we confess our sins, He is faithful and righteous to forgive us our sins and to cleanse us from all unrighteousness.” (1 John 1:9, NASB)
Do not run down a believer out of fellowship, or malign them. This does not help them. Do not get out of fellowship when helping others. Remember, you have failed too. Consider the source as per Galatians 6:1.
“Brethren, even if anyone is caught in any trespass, you who are spiritual, restore such a one in a spirit of gentleness; each one looking to yourself, so that you too will not be tempted.” (Galatians 6:1, NASB)
Do not try to be the Lord’s whip. Rom. 12:19
“Never take your own revenge, beloved, but leave room for the wrath of God, for it is written, "VENGEANCE IS MINE, I WILL REPAY," says the Lord.” (Romans 12:19, NASB)
Give wrath a wide berth. Two angry people cannot communicate very well. Instead, have an attitude of grace. Matt. 18:23.
“"For this reason the kingdom of heaven may be compared to a king who wished to settle accounts with his slaves.” (Matthew 18:23, NASB)