Genesis 4:3 And in process of time it came to pass, that Cain brought of the fruit of the ground an offering unto the Lord. 4 And Abel, he also brought of the firstlings of his flock and of the fat thereof. And the Lord had respect unto Abel and to his offering.
[Patriarchs & Prophets pp 71] Cain and Abel, the sons of Adam, differed widely in character. Abel had a spirit of loyalty to God; he saw justice and mercy in the Creator's dealings with the fallen race, and gratefully accepted the hope of redemption. But Cain cherished feelings of rebellion, and murmured against God because of the curse pronounced upon the earth and upon the human race for Adam's sin. He permitted his mind to run in the same channel that led to Satan's fall—indulging the desire for self-exaltation and questioning the divine justice and authority.
These brothers were tested, as Adam had been tested before them, to prove whether they would believe and obey the word of God. They were acquainted with the provision made for the salvation of man, and understood the system of offerings which God had ordained. They knew that in these offerings they were to express faith in the Savior whom the offerings typified, and at the same time to acknowledge their total dependence on Him for pardon; and they knew that by thus conforming to the divine plan for their redemption, they were giving proof of their obedience to the will of God.
Without the shedding of blood there could be no remission of sin; and they were to show their faith in the blood of Christ as the promised atonement by offering the firstlings of the flock in sacrifice. Besides this, the first fruits of the earth were to be presented before the Lord as a thank offering. The two brothers erected their altars alike, and each brought an offering. Abel presented a sacrifice from the flock, in accordance with the Lord's directions. “And the Lord had respect unto Abel and to his offering.” Fire flashed from heaven and consumed the sacrifice.
Genesis 4:5 But unto Cain and to his offering he had not respect. And Cain was very wroth, and his countenance fell.
May God add His blessing to the study of His word. “good night” and God bless!