satyasyapihitam mukhamAs you may know, the motto part is just the third line. But it kind of distorts the context in which it makes more sense. This you can read here. I remember the teacher, a very humourous & knowledgeable gentleman who was absolutely against sparing the rod, put particular emphasis on "pushann" - the sustainer. He did so to underscore the importance of nurturing & nourishment in education & that this bringing out of inner talent (hiranmayena) is a rather slow process.
He went on to add that "dandaa maarke sar phodke pratibha bahar naheen aa saktee" though he hardly ever followed his own counsel.