Commentators explain that just as a lion's roar instinctively causes fear, God's command compels His prophets to speak. Amos justifies his difficult message by stating he has no choice; a divine necessity is laid upon him. Scholars compare this to Paul's "woe is unto me if I preach not the Gospel" and Jeremiah's feeling of God's word as a "burning fire" in his bones. The message isn't from the prophet, but from God through the prophet.