Explanation

The Prophet (may Allah's peace and blessings be upon him) sent ‘Umar ibn al-Khattāb (may Allah be pleased with him) to collect Zakah. When ‘Umar asked Al-‘Abbās ibn ‘Abd al-Muttalib to pay the share due on him, he refused, and so did Khālid ibn al-Walīd and Ibn Jamīl. So ‘Umar went to the Prophet (may Allah's peace and blessings be upon him) to complain to him about the three men. The Prophet (may Allah's peace and blessings be upon him) said that Ibn Jamīl had no excuse for withholding Zakah except that he was poor and Allah made him wealthy, the thing that necessitated his immediate payment of Zakah. As for Khālid, it was unjust to say that he refused to pay Zakah, for he had devoted his armors and war gears to exclusive use in the cause of Allah. By this, he wanted to get closer to Allah by spending something not mandatory on him. So it was impossible that he would withhold a mandatory charity. As for Al-‘Abbās, the Prophet (may Allah's peace and blessings be upon him) said that he would pay Zakah on his behalf, probably because of his being held in high esteem as indicated by: “Do you not know that a man’s uncle is like his father?"