Musnad Ahmad 30:1941

Aswad ibn Amir narrated to us, Abu Bakr ibn Ayyash narrated to us, from Abu Husayn, from Abu Salih, from Abu Hurayrah, who said: The Messenger of Allah, may Allah bless him and grant him peace, said: "Wealth is not from the abundance of worldly goods, but wealth is the wealth of the soul."