In #exodus 6:3, God said Abraham, Isaac, and Jacob didn't know him by the name YHVH. It doesn't mean they didn't know the word "YHVH" but rather a manner of relating to Him. The Bible uses different names for God to emphasize different aspects of his character or the roles he plays in his creation. El Shaddai works thru the world. Elohim creates and judges the world. YHVH is hidden from/revealed to the world in relationship with his people. These are three modes in which the same God operates.
#biblestudy #torah #vaera