3 "So it came about in the course of time that Cain brought an offering to the Lord of the fruit of the ground. 4 Able, on his part also brought of the firstlings of his flock and of their fat portions. And the Lord had regard for Abel and for his offering; 5 but for Cain and for his offering He had no regard. So Cain became very angry and his countenance fell."
It's clear that Cain and Abel had a relationship with God, living outside the Garden of Eden, "Abel was keeper of the flocks and Cain was responsible for tilling the land." Genesis 4:2 It's not exactly clear what Cain's offering was nor do we know what his attitude was in his giving. We do know that God was not pleased with his offering and it didn't sit well with Cain. In Gensis 4:6 "...the Lord said to Cain, Why are you angry? And why has your countenance fallen?
All throughout the Old Testament God identifies the type of sacrifices He desires. Offerings were tangible and were considered to be of great value, from first fruits to the best in show. These gifts represented a sacrifice, pointing to the ultimate sacrifice God made for us by shedding His Son's blood on the cross for atonement for our sins.
God no longer requires a blood sacrifice for our sins, Jesus said on the cross, "it is finished." This represents the end of the first covenant with Abraham, it points to the second Covenant with Christ. In His final breaths, Jesus signals that there was no more need for blood sacrifices. He is the ultimate fulfillment to the sacrificial system under the law and out from the law.
Regardless of the past or present time, God asks us to return a portion of all that He provides. The value of the offering is in direct proportion to the cheerfulness in which it is given. Its value is also in relationship to the cost or loss it represents. The story of the widow's mite is a good illustration of this, Mark 23:42-44 tells us, 42 "there came a certain poor widow, and she threw in two mites, which make a farthing. 43 And he called unto him his disciples, and saith unto them, Verily I say unto you, That this poor widow has cast more in, than all they which have cast into the treasury; 44 For all they did cast in of their abundance; but she of her want did cast in all that she had, even all her living."
Do we fully understand that all we have comes from the generous hand of our loving Father in Heaven? God asks that we return a portion of what He has given us; He knows our heart and He knows if our sacrifices and offerings to Him are from a clean pure heart or a defiled heart. It is good to meditate on this before we bring an offering of any kind.
2 Corinthians 9:6-7 "...whoever sows sparingly will also reap sparingly, and whoever sows bountifully will also reap bountifully. 7 Each one must give as he has decided in his heart, not reluctantly or under compulsion, for God loves a cheerful giver."