But unto Cain and to his offering he had not respect. And Cain was very wroth, and his countenance fell.
And the LORD said unto Cain, Why art thou wroth? and why is thy countenance fallen? If thou doest well, shalt thou not be accepted? and if thou doest not well, sin lieth at the door. And unto thee shall be his desire, and thou shalt rule over him. (Genesis 4:5-7, KJV)

In our reading of Genesis, we have now come to the post-fall world. Adam and Eve have conceived children, Cain and Abel. Cain, a tiller of the ground, and Abel, a shepherd.

God has regard for the sacrifice of Abel but not of Cain’s. Why? The text suggests the following reasons:

  1. Cain brought his sacrifice with an unthankful heart, without faith.
  2. Cain brought a sacrifice that was not what God commanded. 2a.Cain brought a sacrifice without blood. Atonement for sin requires a blood sacrifice.
  3. Cain sought to be justified by his sacrificial works, rather than by faith.

Cain Was Without Faith

Cain’s spiritual condition becomes evident quickly. He did not rejoice at his brother’s sacrifice but rather envied him with jealously and anger (v.5). His murder of his brother (v.8) and his impious response to God (v.9) demonstrate that he is a man without a regenerate heart. When he brought his sacrifice to God, he did so without faith. Calvin comments:

Moreover, in the person of Cain is portrayed to us the likeness of a wicked man, who yet desires to be esteemed just, and even arrogates to himself the first place among saints. Such persons truly, by external works, strenuously labor to deserve well at the hands of God; but, retaining a heart inwrapped in deceit, they present to him nothing but a mask; so that, in their labourious and anxious religious worship, there is nothing sincere, nothing but mere pretense. When they afterwards see that they gain no advantage, they betray the venom of their minds; for they not only complain against God, but break forth in manifest fury, so that, if they were able, they would gladly tear him don from his heavenly throne.

-Calvin, Commentary on Genesis 4

Cain Brought a Sacrifice That Was Not Commanded and Was Without Blood

God not only looks at the spiritual condition of Cain but also the manner of sacrifice that he brings. Animal sacrifice was already present in the covenant of grace by implication in Genesis 3:21. Matthew Henry comments: “It is supposed that they were slain, not for food, but for sacrifice, to typify the great sacrifice [Christ’s sacrifice] which, in the latter end of the world, should be offered once for all.”

Several Reformed commentators have noted that Adam would have been the high priest of the covenant at that time. God would have instructed him in the sacrifice and then instructed Cain and Abel in sacrifice as well. Since the first sacrifice offered was an animal sacrifice – and without the shedding blood there is no remission of sins (Heb.9:22) – it follows that Cain and Abel were instructed to bring an animal sacrifice. Abel did this, by faith, and as commanded. We learn from this that God looks not only to our intentions but also to our actions. Our obedience to God’s command is as important as our intent to please Him.

In Douglas Comin’s study of worship throughout the Bible, he quotes John L. Girardeau, 19th cen. Southern Presbyterian, in support of this view:

“Cain, the type of rationalists and fabricators of rites and ceremonies in the house of the Lord, consulted his own wisdom and taste, and ventured to offer in God’s worship the fruit of the ground – an un-bloody sacrifice; while Abel, conforming to the appointments and prescribed usages in which he had been trained, expressed his faith and obedience by offering a lamb.”

What at we see here is the earliest elements of what has come to be known as the Regulative Principle of Worship. The Westminster Confession of Faith in 21.1 sets down this principle which guided much of the reformation of worship in the English church. It states that the “acceptable way of worshipping the true God is instituted by himself” and that we may not worship in “any other way not prescribed in the Holy Scripture.” This wasn’t an invention of the Reformation; it reflects a biblical notion found especially in Deut 12:32: “What thing soever I command you, observe to do it: thou shalt not add thereto, nor diminish from it.” Abel provided the acceptable sacrifice according to what God commanded. Cain did not.

Cain Sought to be Justified by His Works

As suggested by Calvin above, Cain’s sacrifice was a merely “external work”. He did not offer his sacrifice out of a heart of faith, instead offered an unworthy sacrifice, and by doing so sought to win God’s favor. When he did not win that favor, the wicked intentions of his heart became manifest.

Despite this, we read that God was patient with Cain (v.7). He calls him to repent, points him to what God has commanded (that he “doest well”), and tells him that his repentance would bring him favor with God. He warns him that failure to repent will result in greater sin.

Praise be to God that He does not give us the punishment we deserve immediately upon our sins but calls us to repentance. Failure to heed this call of repentance is what has always separated us from God. Is the Spirit convicting you of sin in your life? If so, repent. Bring it to God in prayer, and He will be merciful. Offer yourself wholly to Him, as Paul tells us in Romans:

I beseech you therefore, brethren, by the mercies of God, that ye present your bodies a living sacrifice, holy, acceptable unto God, which is your reasonable service. (Romans 12:1, KJV)

I am a Reformed Presbyterian. I offer all content as my own personal reflections. I am not a licensed minister.