The Lord looked with favor on Abel and his offering, but on Cain and his offering he did not look with favor. So Cain was very angry, and his face was downcast. Then the Lord said to Cain, “Why are you angry? Why is your face downcast? If you do what is right, will you not be accepted? But if you do not do what is right, sin is crouching at your door; it desires to have you, but you must rule over it.”
Was The Father prepared to accept Cains worship and his offering if he had
“done right,”? God rhetorically answers yes, Cain would be no less than Able, if only he decided on righteousness like his brother.
Can God accept the sacrifice of an unregenerate, wickedly sinful murderer? If not than the teasing that he could be accepted was a sham, a mocking reply, since the Father was never willing to restore Cain to a right spiritual condition in the first place. His worship was never going to be acceptable under Calvinism. Why taunt the man with false hope?
Now outside of Calvinism, according to the Bible, Cain, who 1 John 3 described as
“belonging to the evil one,” is offered the same kind of opportunity to share pure, acceptable worship as anyone else, that’s an incredible thing. That’s very gracious.