John the Apostle
1 John 2:29ESV·traditional attribution

If you know that he is righteous, you may be sure that everyone who practices righteousness has been born of him.

John Calvin Reformed @genevareformer

29. If ye know that he is righteous He again passes on to exhortations, so that he mingles these continually with doctrine throughout the Epistle; but he proves by many arguments that faith is necessarily connected with a holy and pure life.

Matthew Henry Presbyterian @wholebiblehenry

From the blessing of the sacred unction the apostle proceeds in his advice and exhortation to constancy in and with Christ: And now, little children, abide in him, Jo1 2:28. The apostle repeats his kind appellation, little children, which I suppose does not so much denote their diminutiveness as his affection, and therefore, I judge, may be rendered dear children.

Commenting on 1 John 2:28-29

John Gill Reformed Baptist @doctorgill

If ye know that he is righteous,.... That is, Christ, who is righteous as God in his nature and in his works; and as man in his obedience, life, and conversation; and as Mediator, in faithfully discharging the work he undertook; and is the author of an everlasting righteousness, which is imputed by God, revealed in the Gospel, and received by faith; all which they...