Albert Barnes Commentary Amos 3:8

"The lion hath roared; who will not fear? The Lord Jehovah hath spoken; who can but prophesy?" — Amos 3:8 (ASV)

The Lion has roared: who will not fear? The Lord God has spoken: who can but prophesy? — that is, there is cause for you to fear when the Lord roareth from Zion; but if you fear not, God’s prophets dare not but fear.

So Paul says, “necessity is laid upon me; yea, woe is unto me if I preach not the Gospel! For if I do this thing willingly, I have a reward; but if against my will, a dispensation of the Gospel is committed unto me” (1 Corinthians 9:16–17).

And Peter and John, “Whether it be right in the sight of God to hearken unto you more than unto God, judge ye! For we cannot but speak the things which we have seen and heard” (Acts 4:19–20).

Moses was not excused, though slow of speech; nor Isaiah, though of polluted lips; nor Jeremiah, because he was a child; but God said, “Say not, I am child, for thou shalt go to all that I shall send thee, and whatsoever I command thee thou shalt speak” (Jeremiah 1:7).

And Ezekiel was commanded, “be not rebellious, like that rebellious house” (Ezekiel 2:8). And when Jeremiah would keep silence, he says, “His Word was in mine heart as a burning fire, shut up in my bones, and I was weary with forbearing, and I could not stay” (Jeremiah 20:9).