Commentators explain that when Amos said, "I was no prophet," he wasn't disqualifying himself. Instead, he was highlighting the extraordinary nature of his mission. He wasn't from the established "schools of the prophets" or a prophetic family. His authority came directly and miraculously from God, who "took" him from his flock. As John Calvin notes, this unconventional call actually gave Amos more authority, proving his message was not of human origin but a direct command from heaven.