Our relationship is eternal. But if somebody lags behind, so in spite of our eternal relationship one may not meet other at the destination. Just like a flock of birds—although very intimately related, everyone of them has to fly in the sky by individual strength. If one is less strong, the other cannot keep him in the sky. That is the law of nature. So long everyone of us is strong in Krishna Consciousness, there is no doubt, you can fly in the spiritual sky and meet together without failure. Therefore, individual strength is most important. And that individual strength is achieved in the association of devotees also. So you can make your own judgment.
(Srila Prabhupada's letter to Satsvarupa—San Francisco 20 September, 1968)