Contradiction with Proverbs 15:1
This verse suggests that a soft answer can turn away wrath, which aligns with the idea of wise words healing, rather than contradicting the impact of rash words as Proverbs 12:18 indicates.
Proverbs 15:1: A soft answer turneth away wrath: but grievous words stir up anger.
Contradiction with James 3:6
This verse describes the tongue as a fire, a world of iniquity, which aligns with the harmful potential of words in Proverbs 12:18, rather than contradicting it.
James 3:6: And the tongue [is] a fire, a world of iniquity: so is the tongue among our members, that it defileth the whole body, and setteth on fire the course of nature; and it is set on fire of hell. [course: Gr. wheel]