Exodus 6:3. God tells Moses, "I appeared to Abraham, Isaac, and Jacob as God Almighty" (Exodus 6:3), and that by his name, the Lord, he did not make himself known to them. Genesis tells it another way: "At that time people began to invoke the name of the Lord" (Genesis 4:26), in Enosh's day, long before Abraham. The bush in Exodus 3:15 gives Moses the name too, but says nothing about the ancestors lacking it.
A study Bible, the New Oxford Annotated Bible, says Genesis and Exodus preserve two different old stories about the name. John Barton, in his history of the Bible, says scholars use this difference to tell apart the older written accounts woven into these books. Barton adds that scholars still argue over how many there were.
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