Contradiction with Proverbs 10:19
This verse states that in the multitude of words there is sin, which contradicts Psalms 37:30 that implies the righteous speak wisdom without sin.
Proverbs 10:19: In the multitude of words there wanteth not sin: but he that refraineth his lips [is] wise.
Contradiction with James 3:8
This verse claims that no one can tame the tongue and it is full of deadly poison, which contradicts Psalms 37:30 suggesting controlled and wise speech.
James 3:8: But the tongue can no man tame; [it is] an unruly evil, full of deadly poison.
Contradiction with Matthew 12:36
This verse warns that people will have to account for every idle word spoken, differing from Psalms 37:30, which assumes righteousness in speech.
Matthew 12:36: But I say unto you, That every idle word that men shall speak, they shall give account thereof in the day of judgment.
Contradiction with Proverbs 17:28
This verse suggests that even a fool is considered wise if silent, contradicting the notion in Psalms 37:30 that wise speech comes from the righteous.
Proverbs 17:28: Even a fool, when he holdeth his peace, is counted wise: [and] he that shutteth his lips [is esteemed] a man of understanding.
Contradiction with Ecclesiastes 5:2
Advises not to be rash with words, which contrasts with Psalms 37:30, where speech of the righteous is portrayed as inherently wise.
Ecclesiastes 5:2: Be not rash with thy mouth, and let not thine heart be hasty to utter [any] thing before God: for God [is] in heaven, and thou upon earth: therefore let thy words be few. [thing: or, word]