SB 1.2.20-21: How to know God

SB 1.2.20: Thus established in the mode of unalloyed goodness, the man whose mind has been enlivened by contact with devotional service to the Lord gains positive scientific knowledge of the Personality of Godhead in the stage of liberation from all material association.

The brahminical stage is the highest stage of human life because of its good qualities. So one cannot be a devotee unless one at least qualifies as a brāhmaṇa. The devotee is already a brāhmaṇa by action. But that is not the end of it. As referred to above, such a brāhmaṇa has to become a Vaiṣṇava in fact to be actually in the transcendental stage. A pure Vaiṣṇava is a liberated soul and is transcendental even to the position of abrāhmaṇa. In the material stage even a brāhmaṇa is also a conditioned soul because although in the brahminical stage the conception of Brahman or transcendence is realized, scientific knowledge of the Supreme Lord is lacking. One has to surpass the brahminical stage and reach the vasudeva stage to understand the Personality of Godhead, Kṛṣṇa.