Contradiction with Proverbs 3:5
Proverbs 3:5 advises to trust in the Lord rather than in men, which could contradict the commendation of a man's diligence in 2 Corinthians 8:22.
Proverbs 3:5: Trust in the LORD with all thine heart; and lean not unto thine own understanding.
Contradiction with Jeremiah 17:5
Jeremiah 17:5 warns against trusting in man, contrasting with the trust placed in the brother mentioned in 2 Corinthians 8:22.
Jeremiah 17:5: Thus saith the LORD; Cursed [be] the man that trusteth in man, and maketh flesh his arm, and whose heart departeth from the LORD.
Contradiction with Psalm 118:8
Psalm 118:8 suggests it is better to trust in the Lord than in humans, conflicting with the reliance on human diligence in 2 Corinthians 8:22.
Psalm 118:8: [It is] better to trust in the LORD than to put confidence in man.
Contradiction with Isaiah 2:22
Isaiah 2:22 advises to cease from man as he is limited, whereas 2 Corinthians 8:22 emphasizes confidence in a person's diligence.
Isaiah 2:22: Cease ye from man, whose breath [is] in his nostrils: for wherein is he to be accounted of?
Contradiction with Micah 7:5
Micah 7:5 cautions against putting confidence in a friend, which may conflict with the trust and commendation given in 2 Corinthians 8:22.
Micah 7:5: Trust ye not in a friend, put ye not confidence in a guide: keep the doors of thy mouth from her that lieth in thy bosom.
Contradiction with Psalm 146:3
Psalm 146:3 reminds not to put trust in princes or mortal men, which can contrast with placing confidence in human effort like in 2 Corinthians 8:22.
Psalm 146:3: Put not your trust in princes, [nor] in the son of man, in whom [there is] no help. [help: or, salvation]