In Genesis 4:26, after the the description of Seth’s son Enos, it says, “…at that time people began to call upon the Name of the Lord. That’s a very interesting statement. To call on the Name of the Lord basically means to worship Him. ‘To call on the name of’ is to pray to, and thus to indicate that you are worshiping a particular god or goddess, and calling on their name. You call on the the name of a false god, if you’re an idolater. The same terminology is used of false worship, as well as true worship. But notice that this is rather far long after Adam and Eve had many children and grandchildren and so on, then you suddenly get this reference to people ‘calling on the Name of the LORD’, and the LORD there is that Name that most of us know YHWH, the proper noun that means ‘the One who creates everything”, “the Creator”. The One who causes to be is literally what YHWH means; the One who causes to exist or causes us to be. This tells us that it was only after some generations that God revealed Himself through that proper Name. And what’s especially interesting is that after the Flood that Name apparently got lost again and had to be the subject of a re-revelation in Exodus 3:14 where Moses at the burning bush at Mt. Sinai says to God in the preceding verse, “Who are You? Who is this talking to me out of the bush?…”. Now Moses of course is thinking polytheistically all the different gods and goddesses and so on. “Which one are you?”. And God says, “I AM who I AM”, using a first person form of the name, and then switches it in the same conversation to the third person – “So tell them YHWH has sent you”. And so what Moses thus receives is the not the first revelation of that Name, but a re-revelation of it.
The fact that there had been a loss of knowledge of God’s personal name is an indication of how far humanity had degenerated , and how they had to be brought back to that knowledge. Of course that Name is not the only Name by which He’s known. He’s know by other names as well, but that was the Name His chosen people called Him up until the time of Christ. But think of the fact between the time of Enos and Exodus 3:14, that personal knowledge of God got lost and had to be reinstated. So you can say that the revelation to Moses and the Exodus story as a bringing back of sorts; i think it’s important to appreciate it because it tells you that there had been a falling away of knowledge of the true God in between the end of Genesis to the beginning of Exodus 3. Moses is highlighting for us the fact that at that re-revelation, which is very clear in Exodus 3 that he doesn’t know the Name YHWH.