Psalms 26:1-12 says:

1 Judge me, O LORD; for I have walked in mine integrity: I have trusted also in the LORD; therefore I shall not slide.
2 Examine me, O LORD, and prove me; try my reins and my heart.
3 For thy lovingkindness is before mine eyes: and I have walked in thy truth.
4 I have not sat with vain persons, neither will I go in with dissemblers.
5 I have hated the congregation of evil doers; and will not sit with the wicked.
6 I will wash mine hands in innocency: so will I compass thine altar, O LORD:
7 That I may publish with the voice of thanksgiving, and tell of all thy wondrous works.
8 LORD, I have loved the habitation of thy house, and the place where thine honour dwelleth.
9 Gather not my soul with sinners, nor my life with bloody men:
10 In whose hands is mischief, and their right hand is full of bribes.
11 But as for me, I will walk in mine integrity: redeem me, and be merciful unto me.
12 My foot standeth in an even place: in the congregations will I bless the LORD.
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David here, by the Spirit of prophecy, speaks of himself as a type of Christ, of whom what he here says of His spotless innocence was fully and extremely true, and of Christ only, and to Him we may apply it. We are complete in Him.

The person that walks in his integrity, yet trusting wholly in the grace of God, is in a state of acceptance, according to the covenant of which Jesus was the Mediator, in virtue of His spotless obedience even unto death.

This person that desires to have his inmost soul searched and proved by the Lord, is aware of the deceitfulness of his own heart; he desires to detect and crush every sin; and he longs to be satisfied with his being a true believer, and to practice the holy commands of God.

Great care to avoid bad company is both good evidence of our integrity, and a good means to keep us in it. Hypocrites and false believers may be found attending on God's ordinances; but it is a good sign of sincerity, if we attend on them, as the psalmist here tells us he did, in the exercise of repentance and conscientious obedience.

He feels his ground firm under him; and, as he delights in blessing the Lord with his people attending worship on earth, he trusts that shortly he shall join the great assembly in heaven, in singing praises to God and to the Lamb for evermore.