ישעיהו יא:ח פירוש: רש״י ואבן עזרא

shall play Heb. וְשִׁעֲשַׁע, shall play.

ושעשע And shall play. In this sense the word has always the reduplication.

over the hole of an old snake over a hole in the ground in which the snake makes its nest [krot in O.F.], a cave. an old snake פֶּתֶן. A snake, when it ages, becomes deaf and is called פֶּתֶן. From then on, it cannot be charmed; as it is said (Psalms 58:6): “Who will not hearken to the voice of charmers.”