KNOWING

There is understanding a thing, and there is knowing it, two different matters. 

In religion, knowing something is knowing it in the same way that you know that water is cold.  It is an experience.  This point is often made in Vedanta when speaking of awakening. 

Awakening is not intellectual but experiential.  In this way, it is difficult to describe and even more difficult, if not impossible, to teach how to attain. 

There are Vedantic scholars who have spent their entire careers studying the many texts of Vedanta, but who have never personally realized awakening. 

By contrast, there are simple monks residing in the forests who have little intellectual knowledge of the scriptures but whose Atman has completely awakened, guided usually, to the extent that it can be, by a guru. 

Not books but daily spiritual practice, sadhana, is required for awakening, although books, up to a point, do not hurt anything.  They are part of the Way of Knowledge so-called in Vedanta, as opposed to the Way of Works and the Way of Devotion.

In the end, though, it is in the lonely search for God that awakening occurs, and when it happens it is a knowing not an understanding.