1. Serve the vani

    There are two ways of association – by vani and by vapuh. Vani means words, and vapuh means physical presence. Physical presence is sometimes appreciable and sometimes not, but vani continues to exist eternally. Therefore we must take advantage of the vani, not the physical presence.    

    (From Srila Prabhupada's Concluding Words to Cc Antya-lila)