Abel brought fat portions from some of the firstborn of his flock. 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 master it."
This scripture bothered me for the longest time - I didn't understand it. What was the big deal? Why couldn't God accept Cain's offering (sacrifice)? What was so special about Abel that God accepted him and his offering (obedience)?
It was because God had given specific instructions as to the offering He wanted. Cain wanted to come up with something on his own. God said; that isn't acceptable, I get to make the rules. Cain became discouraged and angry with God. So God asked Cain: Why are you angry; why are you sad and upset? You know, that if you will do what I have commanded you to do, (what I have decided is right; the rules that I have put into place) you will do well (be approved and accepted by Me).
Cain didn't want to follow the rules, yet he expected the same rewards as those who did. He wanted to do things his way. Sound familiar?
How about you? Do you volunteer at church on Sunday, but refuse God's requirement of remaining sexually pure? Have you decided that your service to the church you attend, or a ministry you volunteer your time at, is sufficient to and equal to the requirement God has made regarding the tithe?
Have you decided to make your own rules? Thinking that, your sacrifice is better than obedience? You don't get to make the rules, and no matter how much you disagree, or dislike them, the fact remains, He desires obedience.