God CAN be seen:
Exod. 33:23: And I will take away my hand, and thou shalt see my backparts.
God CANNOT be seen:
Exod. 33:20: And he said, “Thou canst not see my face; for there shall no man see me and live."
1 Tim. 6:16: Whom no man hath seen nor can see.
James 1:7: Every good gift…cometh down from the Father of lights, with whom there is no variableness…
1 Sam. 15:29: For he is not a man, the he should repent [meaning change his mind]
Gen. 6:6: And it repenteth the Lord that he had made man on earth.
1 Corinthians 7 (whole book. See 1,2,27,39,40)