The purpose of all knowledge is to convince us that we should love Krishna.
One who disbelieves in the sastras [scriptures] is an atheist and we should not consult an atheist, however great he may be. A staunch believer in the sastras, with all their diversities, is the right person from whom to gather real knowledge. Such knowledge may seem inconceivable in the beginning, but when put forward by the proper authority its meaning is revealed and then one no longer has any doubts about it.
One can assimilate the knowledge of the revealed scriptures only by hearing and explaining.
Only when the Lord opens his eyes in the form of sun or moon, the world is able to see. The first person to see is Lord and then we are the next one, we kind of get the remnants. After Lord has seen, then we are the secondaries of anything, This is knowledge. To know this is knowledge, is vidya.
The servants of the Lord are actually the servants of society. They are interested in imparting knowledge of the relationship of the living being with the Supreme Lord, the activities in that transcendental relationship and the ultimate goal of human life. That is the real knowledge which can help society achieve the real aim of human welfare.
Revealed Knowledge is given by the mercy of the Lord to the sincere souls.