7 You will be accepted if you do what is right. But if you refuse to do what is right, then watch out! Sin is crouching at the door, eager to control you. But you must subdue it and be its master.”
For follow-up discussion and general commentary on the topic. Comments are sorted chronologically.
I have spent the first few days of 2022 again doing a bible reading plan, and for the past few days have struggled with this verse. How did Cain know the right way to 'master over sin'? I searched all the verses before 4:7 and only found two commands from God as He spoke to Adam and Eve. I think the first, where he commands about the fruit in the Garden, is the clearest, basically, do this and don't do that. It is a simple matter of obedience. However, there is no clear indication that God spoke any commands to Cain or Abel about making sacrificial offerings or how to master sin. That is my struggle. Where did God tell them that?
It's obvious that God expected them to know, so He must have told them. The ancient tradition holds that God spoke directly to many OT persons, and the fact that Cain was comfortable answering God's question, and He continued to speak directly to many following him, indicates He was still in the business of teaching and leading His creation in person, at least vocally. There is also the fact that oral tradition indicates that future generations would make sacrifices and be expected to behave in a certain way toward God. I like the previous comments about His desire for teaching and second chances, but still struggled with the question of 'How did Cain know what was expected?'
While I also appreciate some commentaries that suggest knowing God's will is embodied in the whole of the Bible, and supported by it's entirety, it still does not answer, for me, how Cain knew.
The only conclusion I can come to is that God must have shared this information. If I go back to my first command from God about the eating of fruit from the Garden, do this, don't do that, I think I find the answer. God told man what to do, some of it is documented some, apparently not.
Through the entirety of my life as a Christian He has spoken to me and his command is simple. Do this, don't do that. In other words, be obedient. Whether I find an earlier Biblical answer to my question is really irrelevant. God has already given me the tools, His Word, my church's teachings, and a mind that allows me to make free will choices. If I choose to be obedient, then God is honored and I have mastery over sin. If not, then I should expect to be confronted for my sin by God, and probably an earthly authority.