What the Prophet (peace and blessings be upon him) was called before his mission

Mujahid narrates from his master: His master told him that when they were building the Ka'bah in the days of Ignorance, a dispute arose among them about placing the Black Stone. So he said: "Appoint someone among you as an arbiter." They said: "The first man who comes along this path (will be our arbiter)." The narrator says: Then the Prophet (peace and blessings be upon him) came, and they said: "The trustworthy one (al-Amin) has come to you." After this the narrator mentioned the whole hadith. The narration concerning the Ka'bah has already passed before this; its narrators are the narrators of the Sahih, except Hilal bin Khabbab, and he is thiqah (trustworthy).

Sayyiduna Ali bin Abi Talib (may Allah be pleased with him) narrates about the building of the Ka'bah: When those people saw the Prophet (peace and blessings be upon him) coming in, they said: "The trustworthy one (al-Amin) has come."
Al-Tabarani recorded it in al-Mu'jam al-Awsat; its narrators are the narrators of the Sahih, except Hafs bin Umar al-Darir and Khalid bin Ar'arah, and both of them are thiqah (trustworthy).