The Torah says, about the generation of Enosh, "then men began to call upon the name of the Lord." The Targumist reads this exactly the opposite way. Targum Pseudo-Jonathan on (Genesis 4:26) renders it: "That was the generation in whose days they began to err, and to make themselves idols, and surnamed their idols by the name of the Word of the Lord."
Idolatry begins with Enosh. Not overt denial of God — something worse. His generation invented the first statues, the first attempts to localize divinity in crafted objects, and then (crucial detail) they called these idols by God's Name. They did not replace God. They relabeled Him.
Why this is more dangerous than outright atheism
Outright rejection of God leaves God recognizable. Idolatry that uses God's Name distorts Him. The worshipper thinks he is praying to the true God, but he is actually praying to a crafted thing, confusing the Name with the image.
This is the Targumist's precise theological nightmare. Authentic worship requires not only a God but a correct understanding of what you are pointing at. Enosh's generation began the slow human habit of building God in our own likeness and then calling the statue by His Name. Every idolatry since has followed the same template.