Genesis 4:3,4

Gen. 4:3, 4. Cain's and Abel's sacrifice. Abel when he comes before God is sensible of his own unworthiness and sinfulness, like the publican, and so is sensible of his need of an atonement, and therefore comes with bloody sacrifices, hereby testifying his faith in the promised great sacrifices. Cain comes with his own righteousness, like the Pharisee, who put God in mind that he paid tithes of all that he possessed. He comes without any propitiation, with the fruit of his ground, and produce of his own labours, as though he could add something to the Most High, by gifts of his own substance; and therefore he was interested in no atonement, for he was not sensible of his need of any, nor did he trust in any; and so being a sinner, and not having perfectly kept God's commandments, sin lay at his door unremoved, and so his offering could not be accepted, for guilt remained to hinder. This reason God intimates, why his offering was not accepted, in what way he says to him, verse Genesis 4:7, "If thou doest well - if thou keepest my commandments, thou and thine offerings shall be accepted; but seeing thou doest not well, as thine own conscience witnesses that in many things thou hast offended, the guilt of sin remains to hinder thy being accepted without an atonement, thy righteousness cannot be accepted, whatever offering thou mayest bring to me." See Bp. Sherlock's Use and Intent of Prophecy, p. 74, 75, and Owen on Hebrews 11:4, p. 18.

Gen. 4:7