Musnad Ahmad 30:2592

Waki' narrated to us, he said: Sufyan narrated to us, from Abu al-Zinad, from al-A'raj, from Abu Hurayrah, he said: The Messenger of Allah, peace and blessings of Allah be upon him, said: "The heart of the old man remains young regarding the love of two things: the accumulation of wealth, and the length of life."