1 John 4:21

This commandment. The writer has just shown that he who does not love his brother cannot love God (verse 20). He now expresses his thought positively (cf. 1 John 1:5, 6; etc.) by referring to a specific commandment. Although Scripture does not contain any command in the form quoted, it is probable that John is referring to Christ’s definition of the first and second commandments (Mark 12:29-31), which is drawn from Deut. 6:4, 5 and Lev. 19:18. He could also have drawn on his own memory of the Saviour’s instruction (John 13:35; 15:12, 17).

From him. In its immediate context this phrase would seem to refer to God, but in this epistle John often reverts to the Son in this manner (see on 1 John 2:27).

John’s recourse to the authority of a specific command from Christ may be compared with that of Paul in his counsel to the Corinthians regarding certain problems affecting the marriage state. In one instance he says, “I speak this by permission,” and in another, “I command, yet not I, but the Lord” (see on 1 Cor. 7:6, 10).

Love his brother. The apostle has shown that hatred for one’s brother and love for God are incompatible (verse 20). Here he emphasizes that love for man is actually a fulfillment of the divine command on the part of those who already love God.