ANYONE WHO GREW up with brothers or sisters knows: sibling rivalry is real. Siblings fight for any number of reasons, especially when they’re young and still learning how to manage their emotions. But over time, an intense rivalry can develop, especially if one child perceives the parents as unfairly favoring another.

And sometimes, unfortunately, the rivalry can result in murder.

In December of 2023, for example, two brothers were arrested, one for murder and the other for attempted murder. According to reports, the 14-year-old became jealous of his 15-year-old brother when the mother bought more Christmas presents for the older son. The younger brother started a fight in the store, which continued after they left the store and went to their grandmother’s house. The younger boy then produced a gun and threatened to shoot his brother in the head.

When their 23-year-old sister intervened — telling the boy to stop fighting because it was Christmas! — he shot her fatally in the chest. The 15-year-old then also pulled a gun, shot his brother in retaliation, and ran. Later, the sheriff understandably lamented how easy it was for kids to get their hands on guns, which the two boys allegedly carried with them all the time.

But such is the world we live in. And for that family, it was not a merry Christmas.

THE FIRST ACT of murder in the biblical narrative comes early, immediately after humanity’s fall into sin. It is also a case of rivalry between humanity’s first pair of siblings. Adam and Eve had two sons, first Cain and then Abel. Each brother brought an offering to God, who looked favorably on Abel’s offering but not Cain’s. Although the text is not entirely clear on the matter, it seems that Abel had brought his best to God but Cain had not. When God therefore favored his younger brother, Cain became resentful and jealous. God’s response to his anger is instructive:

Why are you angry? Why is your face downcast? 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 4:6-7, NIV)

God wasn’t being unfair. Somehow, in bringing an offering, Cain had not done what was right. Here, God opens the door for Cain to acknowledge his own fault and warns him to not to fall prey to sin. But Cain ignores God’s counsel, lures his brother out into the field, then kills him and buries the body.

When God later confronts Cain, asking “Where is your brother Abel?” Cain famously replies: “I don’t know. Am I my brother’s keeper?” (Gen 4:9). It’s an evasive response, a rhetorical question which God doesn’t answer.

But if Cain had asked that question of John, the apostle would probably have said, “Yes.”

IN THE OPENING verse of 1 John 3, the apostle marvels at how much God must love us, to call us his children. In verses 2 to 7, he argues that because we are God’s children, we should show a family resemblance to our Father, and live righteously. When he warns his readers in verse 7 not to let anyone lead them astray, he is directly referring to those who were trying to convince them to adopt heretical views. But indirectly, the warning also points all the way back to the deceptive work of Satan in the Garden of Eden, which John alludes to in verses 8 and 9. Verse 10 then contrasts the children of God with the children of the devil; the former live lives of righteousness and love, and the latter do not.

This, then, is the context in which John points to the story of Cain and Abel, and links it with his theme of love:

For this is the message you heard from the beginning: We should love one another. 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. Do not be surprised, my brothers and sisters, if the world hates you. (1 John 3:11-13)

Once again, John thinks back to the Upper Room, and Jesus’ command to his disciples that after he leaves them, they are to love one another as he has loved them (John 15:12, 17). John has apparently already taught that to his people and reminds them of that fact here.

But then he turns to the story of Cain as a counterexample. Again, Satan enters the picture, echoing both Genesis and John’s previous statement that the children of the devil don’t love their brothers and sisters. Cain, apparently, did not truly love either his brother or God. If he had, he would have learned from his mistake and his brother’s example and done what was pleasing to God. God graciously gave him the opportunity to repent, but Cain refused to do so, and acted on his jealousy instead.

Cain, John suggests, hated his younger brother for his righteousness. I imagine them growing up together, with Cain continually taunting Abel for being a “goody-goody” and then leaning even more in the other direction. Darkly, John suggests that just as Cain hated Abel, so too will the world hate anyone who truly follows Jesus in living a righteous life. After all, Jesus himself had said so in the Upper Room (John 15:18-25), and John echoes that warning here.

Indirectly, John may be addressing the situation caused by the schism in the community. Putting these verses together with what he has said already about sin and righteousness, I suspect that he’s helping his readers understand why those who left hated them for trying to hold the line on righteousness. John says, “Don’t be surprised if the world hates you,” but we have to remember that the word “world” is symbolic for John, representing rebellion against God. Thus, he’s probably saying, “I know it’s confusing, but you shouldn’t be shocked that the people who left hate you. Remember what I already told you about not loving the world. You love the Father, but they love the world — so unfortunately, they hate you.”

And as we’ll see, John’s not done with his reference to Cain and the sin of murder.