Those who are not devotees cannot understand the different forms of Viṣṇu and their positions in regard to the creation. Sometimes the atheists argue, "How can a flower stem sprout from the navel of Garbhodakaśāyī Viṣṇu?" They consider all the statements of the śāstras to be stories. As a result of their inexperience in the Absolute Truth and their reluctance to accept authority, they become more and more atheistic; they cannot understand the Supreme Personality of Godhead. But a devotee like Dhruva Mahārāja, by the grace of the Lord, knows all the manifestations of the Lord and their different positions.
It is said that anyone who has even a little of the Lord's grace can understand His glories; others may go on speculating on the Absolute Truth, but they will always be unable to understand the Lord. In other words, unless one comes in contact with a devotee it is not possible to understand the transcendental form or the spiritual world and its transcendental activities.
- SB 4.9.14 Purport