Musnad Ahmad 28:3

Abdullah ibn Bakr narrated to us, he said: Hatim ibn Abi Saghirah narrated from Abu Balj, from Amr ibn Maymun, from Abdullah ibn Amr, who said: The Messenger of Allah (peace and blessings of Allah be upon him) said: "There is no man on the earth who says: 'La ilaha illa Allah' (There is no god but Allah), 'wa Allahu Akbar' (and Allah is the Greatest), 'wa subhan Allah' (and glory be to Allah), 'wa al-hamdu lillah' (and praise be to Allah), 'wa la hawla wa la quwwata illa billah' (and there is no power and no strength except by Allah), except that his sins are expiated, even if they were more than the foam of the sea."