These things did the prophets set forth in a prophetical manner; but they did not, as some allege, [proclaim] that He who was seen by the prophets was a different [God], the Father of all being invisible. Yet this is what those [heretics] declare, who are altogether ignorant of the nature of prophecy.
…The prophets, then, indicated beforehand that God should be seen by men; as the Lord also says, “Blessed are the pure in heart, for they shall see God.”
Irenaeus of Lyons
Against Heresies, Book IV
Chapter XX