Genesis 4:7

Gen. 4:7. "If thou doest well, shalt not thou be accepted; and if thou doest not well, sin lieth at the door." Cain was not accepted in his offering, because he did not well - because, 1. He was a wicked man, led an ill life under the reigning power of the world and the flesh, and therefore his sacrifice was an abomination to the Lord, Proverbs 15:8, a vain oblation, Isaiah 1:13. God had no respect to Cain himself, and therefore no respect to his offering, as the manner of the expression verse 5 intimates. But Abel was a righteous man: he is called righteous Abel, Matthew 23:35. His heart was upright, and his life was pious; he was one of those whom God's countenance beholds, Psalms 11:7, and whose prayer is therefore his delight, Proverbs 15:8. God had respect to him as a holy man, and therefore to his offering as a holy offering. The tree must be good, else the fruit cannot be pleasing to the heart-searching God.

2. There was a difference in the offerings they brought. It is expressly said, Hebrews 11:4, Abel's was a more excellent sacrifice than Cain's: either, 1. In the nature of it. Cain's was only a sacrifice of acknowledgment offered to the Creator; the meat-offerings of the first of the ground were no more, and for ought I know might have been offered in innocence. But Abel brought a sacrifice of atonement, the blood whereof was shed in order to remission, thereby owning himself a sinner, deprecating God's wrath, and imploring his favor in a Mediator: or, 2. In the qualities of the offering. Cain brought of the fruit of the ground, anything that came next to hand, what he had not occasion for himself, or was not more charitable. But Abel was curious in the choice of his offering, not the lame, or the lean, or the refuse, but the firstling of the flock, the best he had, and the fat thereof, the best of those best. 3. The great difference was this, that Abel offered in faith, and Cain did not - "Abel was a penitent, like the publican that went away justified; Cain was unhumbled, and his confidence was in himself, like the Pharisee who glorified himself, but he was not so much justified before God." Henry on verse Genesis 4:3-5.

["If thou doest not well, sin lieth at the door."] Not at Cain's door, but at God's door. His wicked doings lay, as it were, at the door of God's temple, to prevent his admittance and acceptance with God: they stood as a partition-wall between God and him. Wicked men's sins are a cloud which their prayers cannot pass through, and which hinders their offerings from being brought into the holy place: they are a thick veil before the door of the holiest of all, to hinder their access to God. 1 John 3:21; 1 John 3:22, "Beloved, if our heart condemn us not, then have we confidence towards God, and whatsoever we ask, we receive of him, because we keep his commandments, and do those things that are pleasing in his sight."

Gen. 4:14