Mishnah Chagigah on Abandoning the Torah

"'Who is 'a crooked one who cannot be straightened' (Ecclesiastes 1:15)? Rabbi Shim'on ben Yochai says: We do not refer to someone as 'crooked' unless he was straight at first and then became crooked. And who is this? This is a Torah scholar who abandons the Torah."

-- Mishnah, Chagigah 1:7

Sefer haZohar on the Engraved Name of Rabbi Shim'on bar Yochai

"The blessed Holy One engraved the image of Rabbi Shim'on bar Yochai above and his voice ascends ever upward, and is crowned with the holy crown, until the blessed Holy One is crowned with him in all the worlds and is glorified through him. About him is written: 'And he said to me: You are my servant, Israel, in whom I glory' (Isaiah 49:3). From the day that the blessed Holy One created the world, Rabbi Shim'on bar Yochai was present before the blessed Holy One and was with him; and the blessed Holy One call him by His name."

 -- Sefer haZohar 3:61a