Surah 26. Ash-Shuara, Ayah 107

Amin=one to whom a trust has been given, with several shades of meaning implied: e.g., (1) worthy of trust, (2) bound to deliver his trust, as a prophet is bound to deliver his Message, (3) bound to act entirely as directed by the trust, as a prophet is bound to give only the Message of Allah, and not add anything of his own, and (4) not seeking any interest of his own.