Devotee (2): Prabhupada, how can one know whether he’ll be going back home to Godhead in this lifetime?
Prabhupada: Yes, believe in Krsna. He gives His word. Janma karma me divyam yo janati tattvatah [Bg 4.9]. Krsna says, “Anyone who understands Me in truth,” tyaktva deham punar janma naiti, “he doesn’t accept any more material body; he comes to Me.” That’s it. The guarantee is there. So you try to understand Krsna. If you do not understand anything more, if you simply accept it without any hypocrisy, that “Krsna is the Supreme Personality of Godhead. He’ll protect me. Let me serve His lotus feet as far as possible,” this much qualification is sufficient. But if you have got still doubt about Krsna, then you try to understand Krsna. Be without any doubt that Krsna is the Supreme Personality of Godhead. Then your everything is guaranteed. Tattvatah. Therefore Krsna says, yo janati tattvatah.
From Srila Prabhupada’s lecture on Srimad-Bhagavatam 1.16.23 — January 19, 1974, Honolulu