From: "A Thematic Commentary on the Quran" - Muhammad al-Ghazali
Ibn Kathir reported that an influential man from Syria used to visit Umar ibn al-Khattab, the second Caliph, in Madinah regularly; then, one day, having been away for longer than usual Umar enquired after him and was told that the man had taken to drinking heavily. Umar wrote him a letter saying:
For your sake, I praise God, there is no God but He. He forgives sins and accepts repentance; His punishment is severe and His bounty is infinite. There is no God but He, and all shall return to Him.
He then turned to those around him and asked them to pray that God might accept the man's repentance. When the letter arrived, the man kept repeating the words: "He forgives sins and accepts repentance; His punishment is severe." He was heard saying: "I am being warned of God's punishment and promised His forgiveness," until he broke down sobbing, and from that day he abstained from drinking for good. When the news reached Umar, he said: "This is what you should do when someone commits a misdemeanour.
"Advise him, reassure him gently, never let him lose his self-confidence, pray to God for his sake, and do not help Satan to mislead him."
Today there are professed Muslims who have all but given up on God's mercy, and whose sole preoccupation seems to be to castigate and belittle others.