RobH_en_tn/act/03/18.md

God foretold by the mouth of all the prophets

When the prophets spoke, it was as though God himself was speaking because he told them what to say. Alternate translation: "God foretold by telling all of the prophets what to speak"

God foretold

"God spoke about ahead of time" or "God told about before they happened"

the mouth of all the prophets

Here the word "mouth" refers to the words that the prophets spoke and wrote down. Alternate translation: "the words of all the prophets" (See: rc://en/ta/man/translate/figs-metonymy)