Hadith: O ‘Umar, do you not know that a man’s uncle is like his father?

عن أبي هريرة رضي الله عنه قال: «بعث رسول الله صلى الله عليه وسلم عمر رضي الله عنه على الصدقة. فقيل: منع ابن جميل وخالد بن الوليد، والعباس عم رسول الله صلى الله عليه وسلم . فقال رسول الله صلى الله عليه وسلم ما يَنْقِم ابن جميل إلا أن كان فقيرا: فأغناه الله؟ وأما خالد: فإنكم تظلمون خالدا؛ فقد احْتَبَسَ أَدْرَاعَهُ وَأَعْتَادَهُ في سبيل الله. وأما العباس: فهي عليَّ ومثلها. ثم قال: يا عمر، أما شَعَرْتَ أن عمَّ الرجل صِنْوُ أبيه؟».
[صحيح] - [متفق عليه]

Abu Hurayrah (may Allah be pleased with him) reported: The Messenger of Allah (may Allah’s peace and blessings be upon him) sent ‘Umar (may Allah be pleased with him) to collect the charity. It was said that Ibn Jamīl, Khālid ibn al-Walīd, and Al-‘Abbās, the Prophet's uncle withheld it. Thereupon, the Messenger of Allah (may Allah’s peace and blessings be upon him) said: "How come that Ibn Jameīl withheld it; was he not poor then made rich by Allah?" As for Khālid, you are doing him injustice for he devoted his armor and war gear to the cause of Allah. As for Al-‘Abbās, the charity due on him and the like of it are upon me." Then he said: "O ‘Umar, do you not know that a man’s uncle is like his father?"
Sahih/Authentic. - [Al-Bukhari and Muslim]

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?"