Sayyiduna Abu Murrah al-Ta'ifi (may Allah be pleased with him) says: I heard the Prophet (peace and blessings be upon him) saying: "Allah Almighty says: O son of Adam, offer four rak'ahs for My sake in the early part of the day, and I will suffice you until the last part of it (the day)."
Ahmad recorded it, and its narrators are the narrators of the Sahih.