The lesson that Cain needed to learn is the lesson that every person who comes to Christ for the first time in sincere repentance must learn. It was the lesson that Abel had already learnt. God is no man’s debtor. Forgiveness, pardon and acceptance with him are blessings that are indeed beyond our reach. He will always reserve the right to give them freely without regard to any other consideration. Cain’s pride could not bear the thought that Abel had something he did not have. In reality Cain had misunderstood, for Abel was not accepted by God for anything in Abel himself, but this was beyond his understanding for he did not grasp the meaning of grace. The intensity of this feeling in Cain’s heart teaches us about the hostility that exists between the unbeliever and the believer in all cases. That hostility is not always apparent to the unbeliever, but an event like this in which God makes clear his preference, brings it out into the open.
Why was Cain’s reaction so strong? This passage shows us that the deepest feelings are stirred in the unbeliever over the matter of true religion, over the matter of acceptance with God. This, they know, is the ultimate court of judgment . To be rejected here is more devastating than to be rejected anywhere else. Many of course realise that they will be rejected by God in the last day and do not attempt to come, but Cain was not one of these. He was among those who come to God in their self-righteousness, hoping to be accepted as they are. They vainly deceive themselves that they are good enough for God and that he will be pleased, flattered even, that they have come. They may bring much to God in the way of self-sacrifice or self-denial, but it is all their own work, their own merit. Cain seems to have put much effort into his religious devotions to God. If he had not done so then he would have cared little when his offering was not respected. The unbeliever comes to worship with no comprehension of how great is his sin, his need of pardon, nor of how great is the holiness of God. If he knew this, he would not dare to approach God in his own corruption; he would not presume to think that he could be accepted unwashed by a holy God. He believes that God will be pleased with a little improvement, a little tidying up of the life. He believes he can buy God’s favour, and put God in his debt. His offering is given in an entirely different spirit to that of the believer. It is a gift given to God that requires some repayment in turn from God. He hates the thought that he can give nothing to God that that does not already belong to the Lord. He hates the thought that he is powerless to make up for his past sins.
How is it that Cain did not have faith? Was he not also following the instruction of God? Would he have offered anything at all if he did not have faith in his heart? Lack of faith does not mean that a person has no religion, no worship in their life at all. The instinct to worship is so strong in man that he will make some deity for himself and give some form of obeisance to it. But even when worship is directed towards the true God, as here, it is quite possible to worship him without faith. Yes, there is a belief that God exists which is strong enough to make a person go through the motions of religion, but there is a lack of true faith which trusts the Lord, which humbles the heart, and teaches us that salvation must be a free gift, and that we are unworthy to approach God at all.