(Krishna visiting His devotee, Bilvamangala Thakura—click to enlarge)
Prabhupāda: Caitanya Mahāprabhu says,
sādhu saṅga sādhu saṅga sarva śāstra kaya
lava mātra sādhu saṅge sarva siddhi haya
(CC Madhya 22.54)
"Even a moment's association with a pure devotee—all success." Not necessarily that one has to acquire it previous, no. Generally it is so, but sādhu sanga has got its effect. Caitanya Mahāprabhu said, lavamatra sādhu sanga sarva siddhi haya. You have not read in the Sanātana-śikṣā in the Teachings of Lord Caitanya?
Devotee: Does that also apply to reading the words of a pure devotee?
Devotee: Even a little association with your books has the same effect?
Prabhupāda: Effect, of course, it requires both the things. One must be very eager to take it. Just like Mahārāja Parīkṣit heard Śrīmad-Bhāgavatam, and there are so many others. They are also reading Śrīmad-Bhāgavatam. So Mahārāja Parīkṣit was very serious. So both things should be serious. Just like the example: the husband and wife must be potent; then there is pregnancy. Otherwise there is no pregnancy. So sewing the seed, the field also must be fertile or receptive, then the seed will fructify. It is reciprocal.
Devotee: If the seed starts to sprout and it lacks sufficient facilities, then it will die completely.
Prabhupāda: Yes. Yes.
Devotee: But if a spiritual seed sprouts, then whatever sprout is made is never lost. Right?
Prabhupāda: Yes. It is not lost, but it is checked. Sometimes he is checked.
Devotee: Because the tendency to revive again.
Prabhupāda: In that way again one has to... That brings the question of previous life. One was advanced so much; it was checked by some reason; he again begins from that point. Just like Bilvamaṅgala Ṭhākura. Bilvamaṅgala Ṭhākura was advanced in his previous life up to bhava-bhakti. Somehow or other, it was checked. But as soon as he heard the words from the prostitute, "Oh, you are so much after the flesh and similar, and bones and skin. If you had been so much eager for Kṛṣṇa, how you would have been disposed," immediately he came to that point and immediately left.
(Srila Prabhupada Room Conversation, Indore, December 13, 1970)