Contradiction with Ecclesiastes 8:11
While Proverbs 6:15 suggests that trouble will come suddenly upon the wicked, Ecclesiastes 8:11 points out that because punishment isn't immediate, people's hearts are set on doing evil.
Ecclesiastes 8:11: Because sentence against an evil work is not executed speedily, therefore the heart of the sons of men is fully set in them to do evil.
Contradiction with Psalm 37:7
Proverbs 6:15 indicates sudden calamity for the wicked, whereas Psalm 37:7 advises patience, suggesting the wicked may thrive for a time.
Psalm 37:7: Rest in the LORD, and wait patiently for him: fret not thyself because of him who prospereth in his way, because of the man who bringeth wicked devices to pass. [Rest in: Heb. Be silent to]
Contradiction with Job 21:7
Proverbs 6:15 implies quick downfall, but Job 21:7 questions why the wicked often live long and prosper.
Job 21:7: Wherefore do the wicked live, become old, yea, are mighty in power?
Contradiction with Jeremiah 12:1
Proverbs 6:15 speaks of imminent calamity for the wicked, yet Jeremiah 12:1 questions why the wicked prosper.
Jeremiah 12:1: Righteous [art] thou, O LORD, when I plead with thee: yet let me talk with thee of [thy] judgments: Wherefore doth the way of the wicked prosper? [wherefore] are all they happy that deal very treacherously? [talk...: or, reason the case with thee]
Contradiction with Psalm 73:3-5
Proverbs 6:15 implies the sudden ruin of the wicked while Psalm 73:3-5 observes their prosperity and ease.
Psalm 73:3-5: For I was envious at the foolish, [when] I saw the prosperity of the wicked.