You think you exist as a body/mind, relatively stably through time. Yet every night your body, mind and consciousness disappear for a few hours, until the waking state returns the next day. In that waking state you remember that you slept, and that you existed the day before. So your "stability" in existence is purely memory in the waking state, which comes and goes, comes and goes.
Identification with your body seems to make sense because then you have an apparently stable existence as a body that lasts 40, 60, 90 years, even though "you" exist for only a few hours each day as the waking state, within which is memory that ties all the waking state experiences together.
This waking state is not even the body, but an appearance that comes to you, and which disappears each evening.
In other words, as an analogy--Nisargadatta's analogy--you are like the flame of a cigarette lighter, that goes on and off all day, all week and month long. The flame, feeling its temporality, identifies with the lighter to gain some endurance and weight, but the lighter does not exist for the flame when the flame is not there. The flame just assumes the lighter was existent when it , itself, was not.
Is this not how we are, a flame during the waking moments that identifies with the body, and both of which disappear with sleep and death?
Just be aware of the flame or consciousness. Immerse in it. Be it. This is true self-inquiry.