During one of his journeys, Guru Nanak Dev Ji
met a Rogue named Sajjan. Sajjan always wore a white dress, displayed his rosary beads and thus posed to be a holyman. He had built a Hindu temple and a Muslim mosque at the courtyard of his residence. He would invite travellers to his residence to rest for the night. During the night, he would take away their goods and money and would kill the travellers. He had a well near his house where he would dump the bodies of the guest he killed.
Guru Nanak Dev Ji arrived at his place and stayed with him for the night. At night, the Guru did not go to bed, which made Sajjan nervous to perform his nefarious act of robbing. Sajjan asked the Guru to take rest and sleep but Guru ji replied, "God's minstrel do not go to sleep till God sends word that he should rest." The Guru then asked Mardana to play the rebec and he sang, “Houses, mansions, palaces painted on all sides are left hollow when thy breath stops. You posses wealth and assets; nothing shall go along with you in the end except the sins you commit. You call yourself clever and smart, but you are unaware that you can perish in a moment. You have not remembered God. You are completely drenched in money. You have not loved the one who gave you the body and breath. When the death comes, you shall tremble helplessly. Have you sung the praises of Lord; He would have been your support at the time of your death.”
When Sajjan listened the Divine melody, he realized that Guru Ji’s words were actually addressed to him. Upon hearly the sermin, he made his obeisance and fell at Guru Ji’s feet, and prayed to him to pardon his sins. Guru Ji said, "Sajjan, in the Sovereignty of God, grace is obtained by two things, open confession and reparation for wrong." Sajjan stood in submission. Guru Nanak Dev Ji asked him to give all of his ill-gotten wealth to the poor. He obeyed the mandate, became a follower of the Guru and started meditating on God regularly.