By nature's way or by God's arrangement, there are four classes of men. The most intelligent class of men is called the brāhmaṇas. Intelligent means one who knows up to the Supreme Lord. And then next intelligent class: the politicians, administrators. Next intelligent class: the mercantile class, traders. And the fourth-class man means worker. They have no intelligence, but they depend on others for their livelihood. So there are first-class, second-class, third-class, fourth-class men everywhere, any part of the world.
So the brāhmaṇas' duty is to give education, intelligence, up to the understanding of the Supreme Absolute Truth, Brahman. The Absolute Truth is called Brahman. So one who knows Brahman, or the Absolute Truth . . . Knowledge means the end of knowledge should be up to the understanding of the Absolute Truth, the original source of everything. Absolute, not relative. Relative truth, everyone knows, but when one comes to the point of understanding the Absolute Truth, the original source of everything . . . There must be original source of everything. That is Brahman.