Rabbi Yochanan, in the name of Yossi, the son. of Zimra, asks, " What is this that is written (Ps. cxx. 3), ( What shall be given unto thee, or what shall be added unto thee, O thou false tongue? The Holy One — blessed be He! — said to the tongue, " All the members of the body are erect, thou only art recumbent; all other members are without, thou art within, and not only so, for I have surrounded thee with two walls, one of bone and the other of flesh. What shall be given to thee, or what shall be added unto thee, O thou false tongue?" Rabbi Yochanan, in the name of Yossi, says, He who slanders is an atheist, for it is written (Ps. xii. 4), ( Who have said, With our tongues will we prevail; our lips are with us; who is lord over us?>w
Why God Walled the Tongue Behind Bone and Flesh
Arakhin 15b (Harris, Hebraic Literature, 1901)