8The lion has roared; who will not fear? The Lord GOD has spoken; who can but prophesy?”
The implication in Amos’ questions boils down to this: the Lord will bring disaster upon Israel, and Amos has no choice but to announce the punishment. He prophesies because the Lord has spoken.
8 The lion has roared; who will not fear? The Lord GOD has spoken; who can but prophesy?”