Musnad Ahmad 30:3605

Sulayman ibn Dawud narrated to us, Shu'bah informed us, from 'Abd al-Rahman ibn 'Abis, he said: I heard Kumayl ibn Ziyad narrating from Abu Hurayrah that the Prophet, peace and blessings of Allah be upon him, said: "Shall I not guide you to a treasure from the treasures of Paradise?" I said: "Yes." He said: "La hawla wa la quwwata illa billah (There is no power and no strength except by Allah)." He said: I think he said: "Allah, the Mighty and Majestic, says: 'My servant has submitted and surrendered.'"