Musnad Abu Ya'la al-Mawsili 115:238

Muhammad ibn Yahya narrated to us, al-Khalil ibn Umar al-Abdi narrated to us, my father narrated to me, from Qatadah, from Anas, who said: The Messenger of Allah (peace and blessings of Allah be upon him) said: "Wealth is not from the abundance of worldly goods, but rather wealth is the richness of the soul."