Walk through Amos, verse by verse, with the great Bible Commentaries of Matthew Henry (1662 - 1714) & Adam Clarke (1760 - 1832)
3:7
Surely the Lord GOD will do nothing, but he revealeth his secret unto his servants the prophets. KJV
{For the Lord God shall not make a word, no but he show his private to his servants (the) prophets.} Wycliffe's Bible
Observe, God’s prophets are his servants, whom he employs to go on his errands to the children of men. The secret of God is with them; His prophets, to whom he has spoken in secret by dreams and visions, cannot but speak in public to the people what they have heard from God.