Sayyiduna Ka'b bin Malik (may Allah be pleased with him), who was one of the three who stayed behind and whose repentance Allah then accepted, said to the Prophet (peace and blessings be upon him): "Part of my repentance is that I will speak nothing but the truth, and that I give all my wealth in charity in the way of Allah and His Messenger." The Prophet (peace and blessings be upon him) said: "Keep some of your wealth with you."
Hadith Referenceالمعجم الكبير للطبراني / باب الكاف / 16151