James 3:6 describes the tongue as a fire; here it is untamable poison, both emphasizing its destructive power.

Deuteronomy 32:33 describes the poison of serpents and venom of asps — the same toxic imagery James applies to the tongue.

Psalm 58:4 directly says the wicked have venom like a serpent — a clear OT source for James's claim of deadly poison in the tongue.

Psalm 140:3 explicitly mentions venom of asps under lips — nearly identical to James's description of the tongue's deadly poison.

Romans 3:13 quotes the same venom-of-asps imagery from the Psalms, showing James draws on a common biblical motif of sinful speech.

Mark 5:4 describes a demon-possessed man no one could tame — a parallel to the tongue that no human can tame.

Psalm 55:21 describes smooth speech hiding deadly intent, echoing the 'deadly poison' of the tongue in this verse.

Psalm 59:7 portrays the wicked's words as swords from their lips — the same destructive speech James says is untamable and poisonous.

Psalm 64:3 sharpens the tongue as a weapon with bitter words — echoing James's image of the tongue's deadly poison.