As per Upnishad, Gyan should not be given to anyone. There should be pre-qualification criteria. It is very well defined in Upnishad and Srimad Bhagvat Geeta. Geeta says," इदं ते नातपस्काय, ना भक्ताय कदाचन: !, न च शुश्रूषावे वाच्यं न च मा योभ्यासुयती !!. गीता १८-७.
आत्मज्ञान (Knowledge about Soul) should not be given to, one who does made any concentrated efforts in getting knowledge. One who is not believe in GOD. One who is not ready to listen anything about GOD, his existence and presence in the Universe. Finally, to one who is against GOD, Who challenges GOD's existence in his/her capacity. Those four types of human are not qualified to be given गुह्यज्ञान.Greek Philosopher सॉक्रेटिस, used to give knowledge to anyone and everyone. Whom so he find on road, near his house or any place. Finally, he had been sent behind bar for several years. He was Poisoned.
That's what Srimad Bhagvat Geeta emphasized, to check pre-qualification for knowledge transfer.....
