Azriel of Gerona, Commentary on Talmudic Aggadoth, p. 40

Jewish Mysticism
Insofar as [the prophet] was sitting and studying, and would cleave his thought above, the wondrous entities [i.e., the sefirot] were engraved upon his heart, and by means of this emanation and this cleaving of thought the entities were increased and expanded, and from the joy they were revealed to him. In this manner was the drawing down of prophecy (hamshakhat ha-nevu’ah), for the prophet would concentrate [his mind] (mitboded) and intend his heart and cleave his thought above. And in accordance with the cleaving of prophecy (devequt ha-nevu’ah) the prophet would see and know what would occur in the future.

Translated by Elliot Wolfson in Through a Speculum that Shines- Vision and Imagination in Medieval Jewish Mysticism, Princeton- Princeton University Press, 1994.