The four bodhisattva vows are – in one sense – a response to the four noble truths.
The first two noble truths are that our life is unsatisfactory (‘suffering’, in the traditional language), and the cause of that suffering is ignorance, which creates a belief that there is a permanent self, which in turn causes desire, aversion and attachment, which perpetuates suffering.
The third noble truth is that there’s a way out of this suffering, which the fourth noble truth identifies: the noble eightfold path.
It is, quintessentially, a solo perspective. Someone living alone on an island or living a solitary existence in the forest could practice these four noble truths.
The bodhisattva vows aren’t like that. They are a creative and compassionate response to suffering, not primarily through recognizing the unreality of a fixed self, but by recognizing and trying to live within the oneness of everything.
The term ‘bodhisattva’ was originally used for the Buddha alone, describing his 500 lives before he became the Buddha.
It was only in the Mahayana sutras that bodhisattva became wider in meaning, and eventually ubiquitous. For example, in the Lotus sutra, there is a scene where countless bodhisattvas, who have been concealing themselves for aeons in an empty space within the earth, burst forth.
Mahayana practitioners often refer to fellow practitioners as bodhisattvas.
Just as the first of the pre-socratic philosophers Thales said,”Everything is full of gods”, from the Mahayana perspective everything is, as it were, full of bodhisattvas.
So when we talk in terms of the first bodhisattva vow—All living beings, I vow to save them- we’re not talking about a unitary self being compassionate towards other unitary selves and things. We’re talking about an entirely reconfigured world and person, which is entirely
bodhisattvas.