This is the process: we have to follow the previous acaryas. That is Vedic system. In the very beginning of this chapter Krsna said, evam parampara-praptam imam rajarsayo viduh [Bg. 4.2].

We haven’t got to make any research, modern understanding. There is no question of modern understanding. We are all following the old, ancient understanding. Now, even from ordinary platform, the eating, sleeping, mating and defending, is that modern? It is not modern. Formerly also, all living entities were eating, they were sleeping, they were having sex intercourse and they were defending. The main business is… Nothing is modernized. You can say modernized, but the principle is the same, old system. Nobody can change. The people are dying also, janma-mrtyu-jara-vyadhi [Bg. 13.9].

That is also the old system. Everyone is taking birth, everyone is growing, everyone is falling diseased and everyone is dying. Can the modern system stop this? The modern system can say, “Now you do not require to eat, you do not require to sleep,” or “You do not require to have sex,” or “You do not require to defend”? No. The same system. “The old wine in a new bottle.” Similarly, janma-mrtyu-jara-vyadhi, five thousand years before, Krsna said… This is real problem: janma-mrtyu-jara-vyadhi-duhkha-dosanudarsanam. The same problem is still going on.

So it is useless to say that modern time, modern ways, modern things. There is nothing modern. The old thing is going on. So if we follow systematically the previous acaryas, previous system, as Krsna is advising… Krsna does not advise, “Modern.” Five thousand years ago He instructed Bhagavad-gita. Still, He was saying purva purvataraih, purvatamaih. Evam parampara-praptam imam rajarsayo viduh [Bg. 4.2]. This is intelligence. We have to accept the real truth and follow it. It does not mean modern age or previous age, past age. That is not Vedic system. The old system is going on, everything. The sun is also the old. The sun is rising as it was doing in olden times. The moon is also rising. The years and season are changing. Everything is going on. Why we should not accept the system of Vedic knowledge, the oldest of all in the world? There is no history. That is intelligence.

Srila Prabhupada, Talk on Bhagavad-gita 4.15 — April 4, 1974, Bombay