“Now Abel kept flocks, and Cain worked the soil. In the course of time Cain brought some of the fruits of the soil as an offering to the LORD. And Abel also brought an offering—fat portions from some of the firstborn of his flock. The LORD looked with favor on Abel and his offering, but on Cain and his offering he did not look with favor. So Cain was very angry, and his face was downcast” (Gen. 4:4-5).
On the surface, it can seem as if there was an arbitrary choice made by God through His acceptance of Abel’s offering but not Cain’s. On closer scrutiny of the text though, we can see that Cain’s heart was not right when he made his offering, which was the reason God did not accept his offering. Then the LORD said to Cain, “… If you do what is right, will you not be accepted? But if you do not do what is right, sin is crouching at your door; it desires to have you, but you must rule over it” (Gen. 4:7). The apostle John affirms it. He says, “Do not be like Cain, who belonged to the evil one and murdered his brother. And why did he murder him? Because his own actions were evil and his brother’s were righteous” (1 Jn. 3:12). Cain assumed his act of giving his offering to God was like that of the pagan’s belief, which was just a transaction between him and God. He failed to realise that an offering to God is an outward expression of a heart that loves God (Gen. 4:8).
Therefore, the issue of God not accepting his offering was not about fruits being not as good as a lamb, but rather, Cain’s offering masked an unrighteous attitude. God rebuked Cain, and he reacted in anger. His anger manifested itself in jealousy of his righteous brother (cf. Heb. 11:4), which ended in his killing of him.
Notwithstanding that, God in His grace, simply asked him gently, “Why are you angry? Why is your face downcast?” (Gen. 4:6). These are the best questions to ask someone or even ourselves when we are jealous: Why are you angry? Why do you resent that person?
Sadly, instead of recognising that the condition of his heart and his attitude towards God determined whether or not God would accept his offering, Cain killed Abel.
It is easy for one to worship God on the outside while stubbornly not living in accordance with His ways on the inside. Jude mentions about people who are outwardly religious but use religious activities to hide their sinful lives: “Woe to them! They have taken the way of Cain” (Jude 11a). We can be faithfully serving God, singing Him praises, and giving sacrificially for the furtherance of His Kingdom, but God doesn’t want any of these if our hearts are not right with Him.