Let integrity and uprightness preserve me - The word here rendered “integrity” means properly “perfection.” See it explained in the notes at Job 1:1. The language here may refer either:
(a) to God - as denoting His perfection and uprightness, and then the psalmist’s prayer would be that He, a righteous God, would keep him; or
(b) to his own integrity and uprightness of character, and then the prayer would be that that might be the means of keeping him, as the ground of his safety, under the government of a righteous God; or,
(c) which I think the more probable meaning, it may be 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 time of persecution and trouble.
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 bearing on himself and those who had wronged him.
For I wait on thee - That is, I depend on thee, or I rely on thee. This is a reason why he pleaded that God would preserve him. See the notes at Psalms 25:20.