“Then Amos answered Amaziah, 'I was neither a prophet nor the son of a prophet, but I was a shepherd, and I also took care of sycamore-fig trees. But the LORD took me from tending the flock and said to me, Go, prophesy to my people Israel.'” (Amos 7:14-15)
The LORD shows Amos three visions: locusts stripping the land, fire devouring the deep, and a plumb line held against a wall. For the first two Amos intercedes and the LORD relents. For the plumb line: I will spare them no longer; the high places of Isaac will be destroyed. Amaziah the priest of Bethel sends to Jeroboam: Amos is raising a conspiracy against you in the very heart of Israel. He also says to Amos: get out, you seer! Go back to the land of Judah. Earn your bread there and do your prophesying there. Don't prophesy anymore at Bethel. Amos responds: I was neither a prophet nor the son of a prophet, but I was a shepherd, and I also took care of sycamore-fig trees. But the LORD took me from tending the flock and said to me, 'Go, prophesy to my people Israel.'
The Catechism identifies Amos's response as the model of the prophetic call that requires no credentials except the divine commission (CCC 702).
Brothers and sisters, I was a shepherd. God did not call a trained prophet from a prophetic school; he called a shepherd from the fields of Tekoa. The qualification for the prophetic word is not the institution but the encounter: the LORD took me and said go. If God has taken you and said go, the absence of credentials is no objection. The commission is the credential.
Lord God, you take shepherds and send them to speak. Give us the courage of those who go, not because of their credentials, but because you said go. Through Christ our Lord. Amen.