And the tongue is a fire, a world of unrighteousness. The tongue is set among our members, staining the whole body, setting on fire the entire course of life, and set on fire by hell. (Jas 3:6 ESV)
When he says that it is set on fire by hell, it is the same as though he had said, that the outrageousness of the tongue is the flame of the infernal fire. (122) For as heathen poets imagined that the wicked are tormented by the torches of the Furies; so it is true, that Satan by the fans of temptations kindles the fire of all evils in the world: but James means, that fire, sent by Satan, is most easily caught by the tongue, so that it immediately burns; in short, that it is a material fitted for receiving or fostering and increasing the fire of hell.
(122) “A bad tongue is the organ of the devil.” — Estius.
–John Calvin, Commenting on James 3:6