Charles Ellicott Commentary Ezekiel 38:17

"Thus saith the Lord Jehovah: Art thou he of whom I spake in old time by my servants the prophets of Israel, that prophesied in those days for [many] years that I would bring thee against them?" — Ezekiel 38:17 (ASV)

Of whom I have spoken in old time.— This is put in that interrogative form which is often used for emphatic assurance. The word many before “years” is not in the original, but is correctly inserted to mark the accusative of duration. The statement is then an emphatic one, that God had long ago and for a long time foretold by His prophets this attack of Gog. But the name of Gog is not mentioned in any earlier prophecy still existing, nor is it likely that any such prophecies, much less any long series of them, have been lost.

This concurs with many other indications in the prophecy to show that it does not relate to any particular event, but that Gog and his allies represent the enemies of the Church in general, and that the prophet is here depicting the same great and prolonged struggle between evil and good, between the powers of the world and the kingdom of God, which has formed the burden of so much of both earlier and later prophecy.