This Bible contradiction is from the Skeptic's Annotated Bible.

Verses

God

Exodus 19:20 View context

And the LORD came down upon mount Sinai, on the top of the mount: and the LORD called Moses [up] to the top of the mount; and Moses went up.

Exodus 20:22 View context

And the LORD said unto Moses, Thus thou shalt say unto the children of Israel, Ye have seen that I have talked with you from heaven.

Angels

Galatians 3:19 View context

Wherefore then [serveth] the law? It was added because of transgressions, till the seed should come to whom the promise was made; [and it was] ordained by angels in the hand of a mediator.