“There are two ways of association-by vani and by vapu. Vani means words, and vapu 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. Bhagavad-gita, for example, is the vani of Lord Krishna.” (Shrila Prabhupada, Chaitanya Charitamrita, Concluding Words)