James 3:9–12: Why Cursing Contradicts Our Speech
James treats cursing not as a minor slip of temper but as a contradiction of why God gave us speech. The mouth that blesses God cannot also curse people made in his image, because a spring does not pour out fresh and bitter water from one opening.
James 3:1–12: The Tongue, Cursing, and Grace
James treats cursing as more than bad vocabulary. The tongue is small, but it steers the whole life, and the same mouth blessing God and cursing his image-bearers exposes what is filling the heart.
James 3:9–12: Is Cursing a Sin?
James treats cursing people as sin, not mere bad manners. The reason is that the person cursed bears God's image, so the same mouth cannot bless God and curse his handiwork.