It is narrated from Sayyiduna Ka'b bin Malik (may Allah be pleased with him) that when his repentance was accepted, he came to the service of the Messenger of Allah (peace and blessings be upon him) and said: Allah has saved me from this trial because of speaking the truth. I had promised Allah that if my repentance was accepted, I would never tell a lie and I would give all my wealth in charity for Allah and His Messenger (peace and blessings be upon him). The Messenger of Allah (peace and blessings be upon him) said to him: Keep some of your wealth with you, it will be better for you. Sayyiduna Ka'b (may Allah be pleased with him) said: Then I will keep my share which I received from Khaybar.