James 3:8

But the tongue can no man tame - This does not mean that it is never brought under control, but that it is impossible effectually and certainly to subdue it. It would be possible to subdue and domesticate any kind of beasts, but this could not be done with the tongue.

It is an unruly evil - An evil without restraint, to which no certain and effectual check can be applied. Of the truth of this no one can have any doubt, who looks at the condition of the world.

Full of deadly poison - That is, it acts on the happiness of man, and on the peace of society, as poison does on the human frame. The allusion here seems to be to the bite of a venomous reptile. Compare Psalms 140:3, “They have sharpened their tongues like serpent; adders” poison is under their lips.” Romans 3:13, “with their tongues they have used deceit; the poison of asps is under their lips.” Nothing would better describe the mischief that may be done by the tongue. There is no sting of a serpent that does so much evil in the world; there is no poison more deadly to the frame than the poison of the tongue is to the happiness of man. Who, for example, can stand before the power of the slanderer? What mischief can be done in society that can be compared with that which he may do?

- ’Tis slander;

Whose edge is sharper than the sword; whose tongue

Outvenoms all the worms of Nile; whose breath

Rides on the posting winds, and doth belie

All corners of the world: kings, queens, and states,

Maids, matrons, nay, the secrets of the grave

This viperous slander enters.

Shakespeare in Cymbellna.