Sefer HaBahir

They [Mar Rachumai's students] asked him, "Why is Chet formed openly and vowelized with a small patach?" He said to them, "Because all the directions [ruchot] are closed except for the north, which is open for good and evil." They said to him, "For good?!? But isn't it written, 'And behold a stormy wind [ruach] came from the north, a great cloud and flashing fire' (Ezekiel 1:4). And there is not fire except furious anger, as is written, And fire went out from before YHVH and consumed them, and they died' (Leviticus 10:2)." He said to them, "This is not difficult. Here it is at a time when Israel does the will of The Place, while there is at a time when Israel does not do His will. At the time that Israel does not do His will, fire comes close, and at the time that they do His will, the trait of compassion rolls and surrounds, as it is written, 'Lifting up iniquity and passing over transgression' (Micah 7:18)."