This story was related by Imam Azhar Hanif during the MKA retreat
Once there was a gambler who went out for gambling every day. There was a sufi in the area who used to advice this otherwise nice person to quit gambling. But his was so addicted that he could not quit. After the game, he repents, but it carried on.
Every day when he comes back from gambling, the Sufi would have kept a stone in front of the house. That reminds him of what he did, he repents, but the next day comes the same way.
This went on for several years. The stones in front of the house became a huge pile, reminding the gambler of all the sins he accumulated. As he grew old, he was getting more and more concerned about his sins.
The day came when both Sufi and the gambler died and was waiting for resurrection. Sufi to heaven and the gambler to hell. The angel comes and first holds the gambler.
"Peace be on you, come with me. The gates of heaven are open for you"
"Me? No way. I guess you mistook my name. Thats the other man over there. The sufi"
"God's angels do not make mistakes. Its you"
"How come? Can't you see the pile of stones in front of my house? Thats the pile of the sins I did"
"That pile of stones does not count in my book. God has washed out those stones by your repenting tears"
"Holy is God. Is not the Sufi coming with us too?"
"No. He has been too arrogant with you piling stones in front of your house. He thought he is God himself"
Let not anyone tell me I am a sinner. Let me not think of anyone as a sinner. And let us all understand the mercy of God is limitless.