One needs to distinguish a sinner from a penitent.
If you have taken upon yourself the role to rebuke the sinner, guard yourself well, that you do not rebuke the penitent also. How dear the repentant sinner is to God; call to mind the Parable of the Prodigal Son. Therefore, let it be very dear for you, he who has become dear to God.
At one time it happened that a monk succumbed to sin for which he was banished from the monastery. This monk went to St. Anthony, confessed his sin, repented and remained with Anthony for a period of time. Then Anthony sent him back again to the monastery but they did not receive him and, again, they banished him. Again, the penitent came to Anthony. Again, Anthony sent him back to the monastery with a message to the fathers of the monastery:
"One boat experienced shipwreck and lost its cargo; with great difficulty did that boat arrive in the harbor and you wish to drown even that which was saved from drowning!"
Hearing this wise message, the fathers received with joy the penitent brother into the monastery.