Rabbi Moshe Cordovero on Prerequisities to the Study of Kabbalah

"There are also those who imagine that before pursuing Kabbalah, they must first master the science of astronomy. They have other notions which keep them from following the straight path. They sanctimoniously give themselves the excuse that their bellies are not yet full of the bread and meat of the Gemara. For these poor people, their entire lives will not be sufficient to learn even a bit of Gemara, let alone to fill their bellies so that they could partake of this science and be sated. Thus the poor people go to their eternal rest bereft of wisdom."

-- Rabbi Moshe Cordovero, Or Ne'Erev 11a

Sefer haZohar (Ra'aya Meheimna) on Kabbalah Above Halakhah

"Just as fish must live in the sea, so the sages, the Masters of the Mishnah, must live in the Torah; if they are taken from it, they die immediately. The Tannaim of the Mishnah proliferate in it like the fish in the sea, yet if they are on dry land and are thrown into the sea, not knowing how to swim, they die. But Adam, who was the master of Kabbalah, which is above halakhah, is above all the Tannaim. It says of him: 'He will rule the fish of the sea and the birds of the air' (Genesis 1:26)."

 -- Sefer haZohar (Ra'aya Meheimnah), 3:278a

Tikkunei haZohar on Removing Kabbalah from the Oral Torah

"One who removes Kabbalah from the Oral Torah and the Written Torah, and discourages others from studying it, saying in effect, 'There is nothing but the simple meaning of the Torah and Talmud,' has diverted the flow of the river away from the Garden."

-- Tikkunei haZohar, 82a