The NET Bible gives a conventional translation of God’s warning to Cain in Genesis 4.7 (BEFORE he murders his brother): “If you do not do what is right, sin is crouching at the door. It desires to dominate you, but you must subdue it.”

But the Hebrew is elliptic and ambiguous. The NET apparatus notes that the word translated crouching could also be the name of a demon from ancient near eastern mythology. Thus perhaps, “Sin is a demon, crouching in wait, ready to pounce. It wants to rule over you. You must subdue it.”

Re the way that sin rules over us, John Walton notes:

“When we refuse to take responsibility for our sin, to accept blame for the consequences of our actions, and to be held accountable for what we do and say, we burn down the bridges of reconciliation. The only way back to reconciliation, forgiveness, and God has as its first step a recognition of the problem and repentant desire to do something about it.

To put the problem another way, distance from God is not just because we sin; it is because we enjoy sin, cherish sinful ways, even protect our right to sin, and resist any attempt to harness our depravity.”