Sufyan bin Abdullah Ath-Thaqafi (may Allah be pleased with him) narrated: I said, "O Messenger of Allah! Tell me something about Islam which I will not need to ask anyone other than you." (And in the narration of Abu Usamah: "other than you after you.") The Prophet (peace and blessings be upon him) said, "Say: I believe in Allah, then remain steadfast upon it."