The German sankirtan party had a real energy, they were a powerful team, and there they were in front of Prabhupada and and Srila Prabhupada said, “So, what is the main thing?” and many of them put up their hands, “Book distribution, Srila Prabhupada!” Prabhupada said, “No – what is the main thing?” They became a little taken aback and some suggested, “Preaching, Srila Prabhupada!,” “Chanting!,” a few suggestions were made, but they were all taken aback that book distribution was not the main thing. Then Prabhupada said, “The main thing is you must read these books! I have written these books for you!” And Prabhupada mentioned that it will not be very good if you go out distributing books and people ask you, “What is this book about?” and you say “I do not know, but it is a very good book and you should take it.”

Bhakti Caitanya Swami, Srila Prabhupada Memories #73