James 3:8

Verse 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 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.