Contradiction with Jeremiah 17:5
Jeremiah 17:5 contradicts Psalms 33:21 by stating that trust in man leads to a curse, whereas Psalms 33:21 emphasizes trust in God as a source of rejoicing.
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 Psalms 44:3
Psalms 44:3 suggests victory is through God's intervention, not human effort; Psalms 33:21 focuses on the joy in God due to reliance on Him, potentially presenting human agency differently.
Psalms 44:3: For they got not the land in possession by their own sword, neither did their own arm save them: but thy right hand, and thine arm, and the light of thy countenance, because thou hadst a favour unto them.
Contradiction with Isaiah 31:1
Isaiah 31:1 warns against relying on human strength and alliances rather than God, contrasting with Psalms 33:21 where trust in God brings joy.
Isaiah 31:1: Woe to them that go down to Egypt for help; and stay on horses, and trust in chariots, because [they are] many; and in horsemen, because they are very strong; but they look not unto the Holy One of Israel, neither seek the LORD!