1 John 1:9

If we confess our sins,.... Not to one other; for though it is our duty to confess our faults to our fellow creatures and fellow Christians which are committed against them, yet are under no obligation to confess such as are more immediately against God, and which lie between him and ourselves; or at least it is sufficient to confess and acknowledge in general what sinful creatures we are, without entering into particulars; for confession of sin is to be made to God, against whom it is committed, and who only can pardon: and a man that truly confesses his sin is one that the Spirit of God has convinced of it, and has shown him its exceeding sinfulness, and filled him with a godly sorrow for it, and given him repentance unto salvation, that needeth not to be repented of; and who, under such a sight and sense of sin, and concern for it, comes and acknowledges it before the Lord, humbly imploring, for Christ's sake, his pardoning grace and mercy; and such obtain it:

he is faithful and just to forgive us [our] sins: forgiveness of sin here intends not the act of forgiveness, as in God, proceeding upon the bloodshed and sacrifice of Christ, which is done at once, and includes all sin, past, present, and to come; but an application of pardoning grace to a poor sensible sinner, humbled under a sense of sin, and confessing it before the Lord; and confession of sin is not the cause or condition of pardon, nor of the manifestation of it, but is descriptive of the person, and points him out, to whom God will and does make known his forgiving love; for to whomsoever he grants repentance, he gives the remission of sin; in doing of which he is faithful to his word of promise; such as in Proverbs 28:13; "and just"; in being "true", as the Arabic version adds, to his word; and showing a proper regard to the blood and sacrifice of his Son; for his blood being shed, and hereby satisfaction made to the law and justice of God, it is a righteous thing in him to justify from sin, and forgive the sinner for whom Christ has shed his blood, and not impute it to him, or punish him for it; though the word here used may answer to the Hebrew word צדיק, which sometimes carries in it the notion and idea of mercy and beneficence; hence mercy to the poor is sometimes expressed by righteousness; and the righteous acts of God intend his mercies and benefits unto men; see Daniel 4:27; and so forgiveness of sin springs from the tender mercies of our God, and is both an act of justice and of mercy; of justice, with respect to the blood of Christ, and of pure grace and mercy to the pardoned sinner: the following clause,

and to cleanse us, from all unrighteousness, is but the same thing expressed in different words; for all unrighteousness is sin, and to cleanse from sin is to remove the guilt of it, by an application of the blood of Christ for pardon. The antecedent to the relative "he" in the text, is either God, who is light, and with whom the saints have fellowship; or his Son Jesus Christ, who is the nearest antecedent, and who, being truly God, has a power to forgive sin.