Arabic text
عن كَعْب بن مالك رضي الله عنه قال: قلتُ: يا رسولَ الله، إن مِن تَوبتي أن أَنْخَلِعَ مِنْ مالي؛ صدقةً إلى الله وإلى رسولِه، فقال رسولُ الله صلى الله عليه وسلم : "أمسِكْ عليك بعضَ مالِكَ؛ فهو خيرٌ لكَ".
Translation
Ka‘b ibn Mālik (may Allah be pleased with him) reported: I said: "O Messenger of Allah, I would like to give all of my wealth as a charity for the sake of Allah and His Messenger to make my repentance fully approved." The Prophet (may Allah's peace and blessings be upon him) said: "Keep some of your wealth, for this is better for you."
Explanation
Ka‘b ibn Mālik al-Ansāri (may Allah be pleased with him) was one of three Companions who did not join the battle of Tabūk without a valid excuse but without being guilty of hypocrisy. When the Prophet (may Allah's peace and blessings be upon him) came back, he refrained from talking to them and told his Companions to do the same. They remained in that state of abandonment until Allah, the Exalted, revealed that He forgave their fault. The Prophet and the Companions were pleased with this. Ka‘b was so happy with Allah's pleasure and acceptance of his repentance that he wanted to give his entire fortune in charity for the sake of Allah, the Almighty. However, the Prophet (may Allah's peace and blessings be upon him) instructed him to keep some of his wealth. When Allah, the Almighty, knew about his truthful intention and sincere repentance, He forgave his sins even though he did not actually go through with it. Indeed, Allah does not burden a person beyond his scope. Therefore, Ka‘b gave part of his fortune in charity out of joy with Allah's pleasure and to gain Allah's reward in the Hereafter, and he kept part of it in order to be able to take care of his and his family's expenses. Verily, Allah is Ever-Merciful to His servants.
Source: HadeethEnc.com