I. The first question to be asked is this: What did Cain and Abel know about sacrifice? Although we should certainly have expected Moses to inform us plainly if there had been a direct ordinance to Adam or his sons concerning the offering of fruits or animals, we have no right to expect that he should say more than he has said to make us understand that they received a much more deep and awful kind of communication. If he has laid it down that man is made in the image of God, if he has illustrated that principle after the fall by showing how God met Adam in the garden in the cool of the day and awakened him to a sense of his disobedience, we do not want any further assurance that the children he begat would be born and grow up under the same law.
II. It has been asked again, Was not Abel right in presenting the animal and Cain wrong in presenting the fruits of the earth? I must apply the same rule as before. We are not told this; we may not put a notion of ours into the text. Our Lord revealed Divine analogies in the sower and the seed, as well as in the shepherd and the sheep. It cannot be that he who in dependence and submission offers Him of the fruits of the ground, which it is his calling to rear, is therefore rejected, or will not be taught a deeper love by other means, if at present he lacks it.
III. The sin of Cain a sin of which we have all been guilty was that he supposed God to be an arbitrary Being, whom he by his sacrifice was to conciliate. The worth of Abel's offering arose from this: that he was weak, and that he cast himself upon One whom he knew to be strong; that he had the sense of death, and that he turned to One whence life must come; that he had the sense of wrong, and that he fled to One who must be right. His sacrifice was the mute expression of this helplessness, dependence, confidence.
From this we see: (a) that sacrifice has its ground in something deeper than legal enactments; (b) that sacrifice infers more than the giving up of a thing; (c) that sacrifice has something to do with sin, something to do with thanksgiving; (d) that sacrifice becomes evil and immoral when the offerer attaches any value to his own act and does not attribute the whole worth of it to God.
F. D. Maurice, The Doctrine of Sacrifice Deduced from the Scriptures,p. 1.
References: Genesis 4:4. G. Brooks, Outlines of Sermons,p. 374; B. Waugh, Sunday Magazine(1887), p. 281.