The module describes the bodhisattva as “one who has renounced nirvana for himself and takes a vow to postpone his own entering into nirvana in order to help all other sentient beings to reach it first. For their sakes, he consented to be born again and again into the Round of Samsara, until, in the course of innumerable ages, even the grass and the dust has attained Buddhahood.”
What stands out in your quote above, is the overlooking of something quite simple and yet quite major.
"Who is reborn?"
One might be quick to say "the Buddha" and that is what the mind/thoughts will attempt to make you focus on because that is something that can be known.
The mind/thoughts "believe" that it is a "man" named "buddha" but it keeps one from overlooking …
"Who is reborn?"
It is not a man ... it is you ... the TRUE YOU ... you are BUDDHA nature but the mind/thoughts will not want you to see this because if you do, you will have nothing to search for and then the mind loses it's power and becomes the Servant to the HEART/BUDDHA/INDESCRIBABLE TRUE NATURE\EMPTINESS.
All sentient beings are in BUDDHA.
This is the simplicity that is too simple for the mind, which thrives and stays alive on complexity. However, as one begins to stop using the mind/thoughts to understand ... TRUE NATURE appears. The mind finally sits back in a recliner with its feet up after a long exhausting journey. The mind (who you think you are) must begin to relax back into the recliner to begin to SEE who you TRULY ARE. All the talking about it will only lead you away from what you are IN.
Once you have discovered what you are In ... then Speak from that Space ... that Emptiness.