"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 John 3:12).
The Christian has three fundamental relationships in this world. The first is his relationship with God, the second is his relationship with his brothers and sisters in Christ, and the third is his relationship with unbelievers. In the Old Testament, there are three great sins that are committed against these three relationships. Adam committed the sin of sacrilege when he defied and broke his relationship with God (Genesis 3). Cain committed the sin of fratricide when he murdered his brother (Genesis 4). And the sons of God of Noah’s day committed the sin of intermarriage when they married strange women (Genesis 6). In a general way, these sins are against the eternal Father, the eternal Brother (Son), and the Spirit, who identifies and secures the boundaries of the church.
John devotes a good deal of attention to the second of these sins, the sin of fratricide (brother murder). He says that one of the acid tests of our relationship with our heavenly Brother is how we treat our earthly brothers in Christ. We should “love one another” (1 John 3:11). “Anyone who hates his brother is a murderer” (v. 15).
Cain murdered Abel because he hated his brother’s righteous deeds. We read in Genesis 4:4–5 that God respected Abel and his sacrifices, while God discountenanced Cain and his offering. Abel’s faith was shown outwardly in his obedient actions, and Cain’s rebellion was shown in his. Often we see people take offense when those around them are more righteous than they. If everyone at the office is cheating, and you refuse to join in, you will be ostracized and criticized. If we are living righteously, we won’t take offense when another Christian is also living righteously. If we take offense, it is a sign that something is wrong.
John tells us that the way to deal with the brethren is to give of ourselves and our possessions. Jesus gave of Himself—He even gave His life (v. 16). We are seldom called upon to go so far, but we are called to live sacrificially with one another. More than this, true brotherly living will increase our assurance of salvation and will strengthen our prayer life (vv. 19–22). God will bless us, and the church will grow.
The church often has a problem, the problem of the anger and resentment that one feels against another. Sometimes the grievance is legitimate, but even if legitimate, it is sinful to harbor it. Are you estranged from someone? Is there some way you can take the first steps toward healing that relationship?