John Calvin Commentary Psalms 18:23

"I was also perfect with him, And I kept myself from mine iniquity." — Psalms 18:23 (ASV)

I was also upright with him. All the verbs in this verse are put by David in the future tense, I will be upright, etc. because he does not boast of one act only, or of a good work performed by fits and starts, but of steady perseverance in an upright course.

What I have said before, namely, that David takes God for his judge, as he saw that he was wrongfully and unrighteously condemned by men, appears even more clearly from what he says here, I have been upright with him. The Scriptures, indeed, sometimes speak in similar terms of the saints, to distinguish them from hypocrites, who content themselves with wearing the outward mask of religious observances; but it is to disprove the false reports which were spread against him that David thus confidently appeals to God regarding them.

This is still more fully confirmed by the repetition of the same thing which occurs a little later, According to the cleanness of my hands before his eyes. In these words there is evidently a contrast between the eyes of God and the blinded or malignant eyes of the world; as if he had said, I disregard false and wicked slanders, provided I am pure and upright in the sight of God, whose judgment can never be perverted by malevolent or other vicious and perverse influences.

Moreover, the integrity which he attributes to himself is not perfection but sincerity, which is opposed to pretense and hypocrisy. This may be gathered from the last clause of verse 23, where he says, I have kept myself from my iniquity.

In speaking this way, he tacitly acknowledges that he was not so pure and free from sinful inclinations as to be unaffected by the malice of his enemies; indeed, their malice frequently stirred up indignation within him and wounded him deeply. He therefore had to fight in his own mind against many temptations, for, being human, he must have felt in the flesh on many occasions the stirrings of vexation and anger. But this was the proof of his virtue: that he restrained himself and refrained from whatever he knew to be contrary to the word of God. A person will never persevere in the practice of uprightness and of godliness unless they carefully keep themselves from their iniquity.