How did the Bodhisatta know there was nibbana. Before he had attained it?

Textual Scholarship
1

https://suttacentral.net/mn26/en/bodhi?lang=en&reference=none&highlight=false
Ariyapariyesanā Sutta

Bhikkhus, before my enlightenment, while I was still only an unenlightened Bodhisatta, I too, being myself subject to birth, sought what was also subject to birth; being myself subject to ageing, sickness, death, sorrow, and defilement, I sought what was also subject to ageing, sickness, death, sorrow, and defilement. Then I considered thus: ‘Why, being myself subject to birth, do I seek what is also subject to birth? Why, being myself subject to ageing, sickness, death, sorrow, and defilement, do I seek what is also subject to ageing, sickness, death, sorrow, and defilement? Suppose that, being myself subject to birth, having understood the danger in what is subject to birth, I seek the unborn supreme security from bondage, Nibbāna. Suppose that, being myself subject to ageing, sickness, death, sorrow, and defilement, having understood the danger in what is subject to ageing, sickness, death, sorrow, and defilement, I seek the unageing, unailing, deathless, sorrowless, and undefiled supreme security from bondage, Nibbāna.’

1 Like
2

It was a concept already floating around at the time.

1 Like
3

  • The Bodhisattas have saddhā (confidence/faith) in Nibbāna and in those who have realized it.

  • In times when the concept of Nibbāna is unknown, people may still have ideas about the end of suffering or the Supreme Happiness.

  • Believing in the end of suffering or a Supreme Happiness is a necessary condition for its realization to be possible.

  • Wise people can understand that for those who do not believe in Supreme Happiness or the end of suffering, the fulfillment of the spiritual life is not possible.

1 Like
4

I might add that they don’t become Buddhas overnight. They have had the ability to attain but have renounced it to become a Buddha. They have spent a long time in the attainment of saṅkhārupekkhāñāṇa. They have to know the Buddha and the dhamma and have been conditioning themselves with faith and wisdom for the Bodhisatta “cooking time” (at least 4 uncountables) required for their specialty. Just as you gravitate towards meditation and Theravada, this habit likely comes from past life experiences. There is no question where it comes from for the Bodhisatta.

1 Like
5

I think the idea of attaining the deathless has always been universal. We can see this in different cultures. People desired immortality. However, I think true immortality is Nibbana because when you attain it you will truly be free from birth, aging, and death.

I can kind of understand why many people renounced the household life and went forth as ascetics even before Buddhism. It’s because of this thought, “I’ll eventually grow old and die, so let me seek the path to be free from death while I’m still alive.”
Some who renounced the household life to practice meditation even became paccekabuddhas and realized the impermanence, suffering, and non-self.

Anyone who has attained arahantship is free from death. That’s the beauty of attaining the fourth path and fruit in this life. Although, their body and consciousness are still impermanent, they don’t identify with them anymore. They don’t regard them as “mine” or “me”. So, just because arahants’ body and consciousness are impermanent, we can’t say that they are not free from birth, aging, and death because they really are free from those things. That’s the purpose of the path.

When their body is going to pass away, they don’t get frightened or think “Oh no, I’m going to die”” because they are free from all defilements and birth, aging, and death when they attained arahantship.