Contradiction with Proverbs 15:9
Proverbs 15:26 says the thoughts of the wicked are an abomination to the Lord, while Proverbs 15:9 states the way of the wicked is an abomination to the Lord, focusing on deeds rather than thoughts.
Proverbs 15:9: The way of the wicked [is] an abomination unto the LORD: but he loveth him that followeth after righteousness.
Contradiction with Ecclesiastes 9:3
Proverbs 15:26 condemns wicked thoughts, but Ecclesiastes 9:3 says that madness is in the hearts of men while they live, implying it's somewhat a common human condition.
Ecclesiastes 9:3: This [is] an evil among all [things] that are done under the sun, that [there is] one event unto all: yea, also the heart of the sons of men is full of evil, and madness [is] in their heart while they live, and after that [they go] to the dead.
Contradiction with Mark 7:21-23
Proverbs 15:26 highlights the wickedness of thoughts, whereas Mark 7:21-23 includes several evil actions, blending both thoughts and deeds, not solely focusing on thoughts as an abomination.
Mark 7:21-23: Thefts, covetousness, wickedness, deceit, lasciviousness, an evil eye, blasphemy, pride, foolishness: [covetousness...: Gr. covetousnesses, wickednesses]
Contradiction with Isaiah 55:7
Proverbs 15:26 condemns wicked thoughts, while Isaiah 55:7 suggests that the wicked can forsake their way and thoughts and receive mercy, implying redemption is possible.
Isaiah 55:7: Let the wicked forsake his way, and the unrighteous man his thoughts: and let him return unto the LORD, and he will have mercy upon him; and to our God, for he will abundantly pardon. [the unrighteous...: Heb. the man of iniquity] [abundantly...: Heb. multiply to pardon]
Contradiction with James 3:10-11
Proverbs 15:26 regards only wicked thoughts negatively, but James 3:10-11 talks about the inconsistency of blessings and curses coming from the same mouth, shifting focus to speech rather than solely thoughts.
James 3:10-11: Out of the same mouth proceedeth blessing and cursing. My brethren, these things ought not so to be.