Now you must all carefully follow these four regulative principles (1) No meat eating, (2) No illicit sex life, (3) No intoxication, (4) No gambling. Always be sure to chant minimum sixteen rounds daily.  Study my books carefully, go for sankirtana and engage in Deity worship in the temple.  You are all very sincere boys and girls and now I request you to make your life successful for going back to home, back to Godhead.

(From a letter by Srila Prabhupada to Sons and daughters — Los Angeles 8 May, 1973)