This Bible contradiction is from the Skeptic's Annotated Bible.
Exodus 6:2-3 View context
And God spake unto Moses, and said unto him, I [am] the LORD:
And I appeared unto Abraham, unto Isaac, and unto Jacob, by [the name of] God Almighty, but by my name JEHOVAH was I not known to them.
Exodus 34:14 View context
For thou shalt worship no other god: for the LORD, whose name [is] Jealous, [is] a jealous God:
Exodus 3:14 View context
And God said unto Moses, I AM THAT I AM: and he said, Thus shalt thou say unto the children of Israel, I AM hath sent me unto you.