Zayd bin Aslam narrates from his father: I heard Umar bin al-Khattab (may Allah be pleased with him) say: One day he (peace and blessings be upon him) ordered us to give charity, and that day happened to coincide with my having wealth. So I said: Today I will outdo Abu Bakr (may Allah be pleased with him), if I am ever to outdo him on any day. So I brought half of my wealth, and the Messenger of Allah (peace and blessings be upon him) said: "What have you left for your family?" I said: The same amount as I have given. Then Abu Bakr (may Allah be pleased with him) came and brought all the wealth he had. He (peace and blessings be upon him) said: "What have you left for your family?" He said: I have left Allah and His Messenger (peace and blessings be upon him) for them. Then I said: I can never outdo you in anything.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الزكاة / 7774