1 John 3:12Meaning & Commentary from the Church Fathers

The Apostle confirms by example how great an evil it is to hate one's brother. See, he says, Cain hated his brother and killed him, although he was his own brother. Cain was doing the evil works of his father, the devil. Abel, practicing righteousness, was a son in relation to God. Here the devil is set against God, and evil works against good ones. Therefore Cain, being opposed to his brother, killed him. Such is the explanation according to the course of the discourse. But the Apostle John changed this order for a special reason. After mentioning the devil and saying that those who do evil become his children, it was natural for him to set forth as an example the one who, at the beginning of the world, hastened to become a son of the devil through evil deeds. Having said what was needed about Cain and the lot inherited by those who imitate him, he again returns to love.

He, that is, Cain, acts impiously and hands over his own blood relative to death. He becomes the firstborn and firstfruits of death, and he appears as a teacher to human nature of the path toward murder.

Therefore, where there is hatred, there can be no brotherly love. Be attentive, beloved. He who envies does not love. In him is the sin of the devil. For the devil too cast man down out of envy, because he himself had fallen and envied one who stood. He did not cast him down in order that he himself might rise, but so that he alone would not be fallen. Learn from the example given that envy cannot exist in love. In praise of love it is clearly said, "Love does not envy" (1 Cor 13:4). There was no love in Cain. If there had been no love in Abel, God would not have accepted his sacrifice. When they both made an offering, one from the fruits of the earth and the other from the offspring of the sheep, what do you think, brethren?

John states that Cain was of the evil one because Cain himself did the works of the evil one. Where there is envy, brotherly love is impossible. In the heart of such a man dwells the sin of the evil one, that is, of the devil, since the devil also cast man down through envy. Abel’s works are works of love. Cain’s evil works are works of hatred toward his brother. He not only hates his brother, but also envies his good works.

To explain the necessity of loving one's neighbors according to Christ's commandment, the Apostle points to the terrible consequences of lacking this love. His words may be connected in this way. This is the good tidings which you heard from the beginning, that we should love one another and not be as Cain was. He was of the evil one, a son or follower of the devil, imitating the devil's malice. Cain hated his brother and killed him. Showing that in this murder Cain acted exactly as the devil had acted, when in malice he killed our foreparents Adam and Eve by drawing them into death-bearing sin, Saint John says, "And why did he kill him?" How had Abel wronged or offended Cain? Had he stolen his property, become proud before him, or raised his hand against his elder brother?

Whoever forgets the saving and love-filled word of the Lord must fear lest he experience the cruel lot that Cain experienced. Who does not know that Cain killed his brother Abel? And why did he kill him? Because his own works were evil, while Abel’s works were good and righteous. A mind darkened by impiety, and a heart alien to love and filled with the poison of malice, could not endure Abel’s goodness. The result was fratricide. Such is the fruit of malice. Thus those who hate their neighbor destroy their own soul.

“Cain was of the evil one,” that is, of the devil. The Apostle gives the example of Cain in order to present more vividly the murderous relation of the false teachers toward believers. “He slew his brother,” έσφαξε. The image is taken from the slaughter of sacrificial animals. The verb σφάγειν has precisely this meaning. It is quite possible that by this expression the Apostle wishes to indicate the very manner of the murder committed by Cain. Yet neither Holy Scripture nor Tradition gives any indication of this.

They loved, and did not act toward them as Cain acted toward his brother Abel, killing him. The brotherly love for one another commanded by Christ, even to self-denial, is a quality that excludes hatred, which reaches and leads to fratricide. Its prototype was in Cain. "Who was of the evil one," that is, of the devil (Mt 13:38-39; Mt 6:13 and note; Jn 8:44 and note), by the disposition of his soul. Therefore he performed a devilish deed, killing his brother Abel at the instigation of the murderer from the beginning. He became the first son of the devil and the first murderer. "Killed": the Greek word means to offer a sacrifice by slaughter. He slaughtered Abel, as if offering him in sacrifice. "And why did he kill him?" His works were evil.

According to his usual way of explaining a matter through opposites, the Apostle marks the sign of the devil’s children with a sharp example. This sign is the absence of love for neighbor, seen in Cain the fratricide. If all our righteousness, which reveals us as children of God, is love for neighbor, then the reverse is also true. Nothing but the absence of love for neighbor leads the devil’s children, through envy, to the very height of impiety, even to murder. Cain is the example of this. By this same example of Cain and Abel, the Apostle also explains the hatred of the impious world toward the righteous and humble children of God.

To show more clearly how the children of God may be distinguished from the children of the evil one by love and hatred, the Apostle cites the example of Cain, the fratricide. According to blessed Theophylact, Cain "hastened to become a son of the devil through evil deeds." By his wicked act he offered, as it were, a sacrifice to the father of lies (see Jn 8:44). Cain's original sin was hatred. And against whom? Against his brother. Moreover, he nourished hatred at a time when the first fall had only begun to bring forth its fruits. Is it surprising that now, with evil more greatly developed in the world, many hate Christians?

Since we have the commandment from the beginning that we should love one another, one must not hate a brother. Otherwise we may be found in evil, like Cain, who murdered his brother.