Musnad Ahmad 30:328

Abu Mu'awiyah narrated to us, Al-A'mash narrated to us, from Abu Salih, from Abu Hurairah, who said: The Messenger of Allah (peace and blessings of Allah be upon him) said: "No wealth has ever benefited me as much as the wealth of Abu Bakr has benefited me." Abu Bakr wept and said: "Am I and my wealth anything other than for you, O Messenger of Allah?"