Our advancement in Krsna consciousness is made possible in two ways, by knowledge and renunciation, jnana and tyaga, or tapasya. The more we become renounced from this material world, the more we advance in Krsna consciousness. But we are only able to make such sacrifices and perform tapasya if we have got knowledge….

So I am requesting all of my students to read my books very seriously every day without fail. In this way, if your mind becomes absorbed at least one or two hours daily in the transcendental subject of Srimad-Bhagavatam, Bhagavad-gita, and other books, then very easily you will make advancement in Krsna consciousness….

This restlessness or agitation of the mind cannot be rectified by altering the material circumstances. If we are Krsna conscious, any type of occupation will suit me and we shall always be satisfied. Therefore, I recommend you to read books more and more and try to understand the subject matter from different angles of vision and be always discussing it with your Godbrothers, even while you are working.

(From Srila Prabhupada's letter to: Bhargava  —  Los Angeles 13 June, 1972)