Sulayman bin Yasar (may Allah have mercy on him) says that Ibn Abi Rabi'ah came with the charity wealth over which he was the collector. When he reached the place called al-Harrah, Sayyiduna Umar bin al-Khattab (may Allah be pleased with him) came out to him there; he (Ibn Abi Rabi'ah) set dates, milk and butter before him. The others ate, but Sayyiduna Umar (may Allah be pleased with him) refused to eat. Ibn Abi Rabi'ah said: "By Allah, may Allah set you right, we drink their milk and benefit from them." He said: "O Ibn Abi Rabi'ah! I am not like you; by Allah, you follow behind their tails." (That is, you look after them.)
Hadith Referenceالسنن الكبرى للبيهقي / كتاب قسم الصدقات / 13165