Albert Barnes Commentary Psalms 25:21

"Let integrity and uprightness preserve me, For I wait for thee." — Psalms 25:21 (ASV)

Let integrity and uprightness preserve me. The word rendered here as “integrity” properly means “perfection.” (See the explanation in the notes at Job 1:1). The language here may refer to one of the following:

1. God—as denoting His perfection and uprightness. In this case, the psalmist’s prayer would be that He, a righteous God, would keep him.
2. his own integrity and uprightness of character. Then the prayer would be that this might be the means of keeping him, as the ground of his safety, under the government of a righteous God.
3. the utterance of a prayer that God would show Himself upright and perfect in protecting one who put his trust in Him; one who was wronged and injured by his fellow men; one who fled to God for refuge in times of persecution and trouble. This I think is the more probable meaning.

It was not exactly the divine perfections, as such, on which he relied; nor was it the integrity and purity of his own life; but it was the government of God, considered as just and equal, as it related to himself and those who had wronged him.

For I wait on thee. That is, I depend on you, or I rely on you. This is a reason why he pleaded that God would preserve him. (See the notes at Psalm 25:20).