The School's Motto is from the "ALAVAKA SUTTA" in the Sutta Pitaka of the Tripitaka.
When the yakkha Alavaka first confronted the Buddha, he threatened to exterminate him unless the Buddha answered all his questions. One of the questions he asked was
"Kathansu Parisujjhati?"
"How is one cleansed?"
And the Buddha replied...
"Pannaya Parisujjhati"
"By Wisdom is one cleansed"