Contradiction with Proverbs 27:2
Encourages others to praise you instead of praising yourself, while Psalms 26:7 focuses on proclaiming one's actions with thanksgiving.
Proverbs 27:2: Let another man praise thee, and not thine own mouth; a stranger, and not thine own lips.
Contradiction with Matthew 6:1
Advises doing good deeds in secret for a reward in heaven, which contrasts with openly telling of one's works as seen in Psalms 26:7.
Matthew 6:1: Take heed that ye do not your alms before men, to be seen of them: otherwise ye have no reward of your Father which is in heaven. [alms: or, righteousness] [of your: or, with your]
Contradiction with Matthew 23:12
Says those who humble themselves will be exalted, whereas Psalms 26:7 involves proclaiming one's deeds, which can be seen as self-exalting.
Matthew 23:12: And whosoever shall exalt himself shall be abased; and he that shall humble himself shall be exalted.
Contradiction with James 4:6
Stresses that God opposes the proud but gives grace to the humble, contrasting with the open declaration of deeds found in Psalms 26:7.
James 4:6: But he giveth more grace. Wherefore he saith, God resisteth the proud, but giveth grace unto the humble.