You have to accept anything from the authorized source. So according to Vedic civilization, all knowledge is received from the Vedas, perfect authorized source. Sruti-pramana, evidence from the sruti, from the Vedas, that is perfect. Therefore, according to Vedic civilization, if you want to establish something you have to quote the section or the injunction from the Vedas. Then it is perfect. In learned circle you cannot say anything hodgepodge. That will not be accepted. If you support your statement from the evidence of the Vedas, then you are accepted as authority. Therefore our principle is… Not only our; this is the Vedic principle. You'll find Caitanya Mahaprabhu giving instruction to Sanatana Gosvami, to Rupa Gosvami, or He was talking with Ramananda Raya — in Caitanya-caritamrta you'll find — and quoting support from the Vedas. Although Caitanya Mahaprabhu is God Himself, Krsna, Krsna-Caitanya, but He is not, what is called, autocratic or, what is called, dictator. No. You'll never find Him. Whatever He'll say, immediately He is supported by Vedic evidence. He can say anything. He can manufacture anything. No, that He does not do. He does not violate the principle.
In the Bhagavad-gita also… Krsna is the Supreme Personality of Godhead. He's also quoting from Vedas. He does not say, "I say." He says, but He says on the Vedic authority. He doesn't say anything superfluous. No. Brahma-sutra-padais caiva hetumadbhir viniscitaih [Bg. 13.5]. He said,
yah sastra-vidhim utsrjya
na sa siddhim avapnoti
na sukham na param gatim [Bg. 16.23]
He says sastra, evidence, Vedic evidence, must be accepted.
From Srila Prabhupada's lecture on Bhagavad-gita 16.9 — February 5, 1975, Honolulu