Contradiction with Ecclesiastes 1:18
While Psalms 19:8 states that "the commandment of the Lord is pure, enlightening the eyes," Ecclesiastes suggests that "in much wisdom is much grief: and he that increaseth knowledge increaseth sorrow," contradicting the notion of enlightenment being purely positive.
Ecclesiastes 1:18: For in much wisdom [is] much grief: and he that increaseth knowledge increaseth sorrow.
Contradiction with Proverbs 25:2
Psalms 19:8 portrays divine commandments as enlightening and clear, whereas Proverbs 25:2 speaks to the glory in concealing matters, suggesting divine knowledge is sometimes hidden, rather than openly enlightening.
Proverbs 25:2: [It is] the glory of God to conceal a thing: but the honour of kings [is] to search out a matter.
Contradiction with Isaiah 29:14
Psalms 19:8 states the commandment is enlightening, but Isaiah implies a removal of wisdom by proclaiming that God will proceed to do a marvelous work by destroying the wisdom of their wise men.
Isaiah 29:14: Therefore, behold, I will proceed to do a marvellous work among this people, [even] a marvellous work and a wonder: for the wisdom of their wise [men] shall perish, and the understanding of their prudent [men] shall be hid. [proceed: Heb. add]
Contradiction with Matthew 11:25
Psalms 19:8 asserts that God's commandments enlighten, while in Matthew, Jesus thanks the Father for hiding these things from the wise and prudent, indicating not all divine truths are meant to enlighten everyone.
Matthew 11:25: At that time Jesus answered and said, I thank thee, O Father, Lord of heaven and earth, because thou hast hid these things from the wise and prudent, and hast revealed them unto babes.
Contradiction with 1 Corinthians 1:19
The verse in Psalms suggests commandments are enlightening, yet Corinthians mentions God destroying the wisdom of the wise, contrasting the enlightening nature of divine truths.
1 Corinthians 1:19: For it is written, I will destroy the wisdom of the wise, and will bring to nothing the understanding of the prudent.