Contradiction with Proverbs 29:25
Contradicts because it suggests fearing man, which is a snare, whereas Psalms 56:4 promotes trusting in God without fear of man.
Proverbs 29:25: The fear of man bringeth a snare: but whoso putteth his trust in the LORD shall be safe. [safe: Heb. set on high]
Contradiction with Matthew 10:28
Contradicts as it encourages fearing those who can kill the body, while Psalms 56:4 states there is no need to fear what flesh can do.
Matthew 10:28: And fear not them which kill the body, but are not able to kill the soul: but rather fear him which is able to destroy both soul and body in hell.
Contradiction with Psalm 118:8
Contradicts by implying trust in man might be required in certain instances, whereas Psalms 56:4 promotes exclusive trust in God over fear of man.
Psalm 118:8: [It is] better to trust in the LORD than to put confidence in man.
Contradiction with Isaiah 41:10
Contradicts because it offers reassurance from God not to fear, similar to Psalms 56:4, yet implies fear might arise.
Isaiah 41:10: Fear thou not; for I [am] with thee: be not dismayed; for I [am] thy God: I will strengthen thee; yea, I will help thee; yea, I will uphold thee with the right hand of my righteousness.