Contradiction with Proverbs 10:32
Job 20:13 describes wickedness being relished, while Proverbs 10:32 suggests the righteous speak what is acceptable.
Proverbs 10:32: The lips of the righteous know what is acceptable: but the mouth of the wicked [speaketh] frowardness. [frowardness: Heb. frowardnesses]
Contradiction with Psalm 37:30
Job 20:13 speaks of hiding iniquity under the tongue, whereas Psalm 37:30 describes the mouth of the righteous speaking wisdom.
Psalm 37:30: The mouth of the righteous speaketh wisdom, and his tongue talketh of judgment.
Contradiction with Isaiah 5:20
Job 20:13 describes savoring evil; Isaiah 5:20 warns against calling evil good, highlighting a moral inversion.
Isaiah 5:20: Woe unto them that call evil good, and good evil; that put darkness for light, and light for darkness; that put bitter for sweet, and sweet for bitter! [call...: Heb. say concerning evil, It is good, etc]
Contradiction with Matthew 7:17
Job 20:13 implies delight in wickedness; Matthew 7:17 contrasts this by stating good trees produce good fruit, not evil.
Matthew 7:17: Even so every good tree bringeth forth good fruit; but a corrupt tree bringeth forth evil fruit.
Contradiction with Proverbs 8:7
Job 20:13 implies hiding and savoring iniquity, while Proverbs 8:7 states that the mouth of the righteous speaks truth.
Proverbs 8:7: For my mouth shall speak truth; and wickedness [is] an abomination to my lips. [an...: Heb. the abomination of my lips]