“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. Although Krishna was personally present five thousand years ago and is no longer physically present from the materialistic point of view, Bhagavad-gita continues.” (Shrila Prabhupada, Chaitanya Charitamrita, Concluding Words)