Genesis 4:4 - Wesley's Explanatory Notes

And the Lord God had respect to Abel and to his offering, and shewed his acceptance of it, probably by fire from heaven but to Cain and to his offering he had not respect. We are sure there was a good reason for this difference: that Governor of the world, though an absolute sovereign, doth not act arbitrarily in dispensing his smiles and frowns. There was a difference in the characters of the persons offering: Cain was a wicked man, but Abel was a righteous man, Matthew 23:35. There was a difference in the offerings they brought. Abel's was a more excellent sacrifice than Cain's; Cain's was only a sacrifice of acknowledgment offered to the Creator; the meat — offerings of the fruit of the ground were no more: 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 favour in a Mediator. But the great difference was, Abel offered in faith, and Cain did not. Abel offered with an eye to God's will as his rule, and in dependence upon the promise of a Redeemer. But Cain did not offer in faith, and so it turned into sin to him.