What is the essential nature of all sentient beings?

Why is the Buddha so compassionate, yet able to leisurely watch from the heavens as the sentient beings of the Saha world suffer all kinds of distress? Can the Buddha bear to watch this?

When my mother passed away, I happened to be practicing mirage contemplation. Many years beforehand, I had already made preparations for how to face my mother's death. My mind kept pondering: what is my mother composed of? Does the person "my mother" truly exist? During the process of handling my mother's funeral arrangements, I observed the minds of the sixth and seventh consciousnesses of each person, observing everyone's psychological state, and thus I realized the mirage contemplation. All people appeared so empty and illusory in my mind; I responded to everything like a walking corpse, even though I still felt deep sorrow within.

Then, when the Buddha observes sentient beings with His immeasurable wisdom, what are sentient beings? The universe and the world, human affairs and physical phenomena—what are they all? The physical bodies of sentient beings are particles of the four great elements; their conscious minds are seeds of consciousness. When the Buddha regards sentient beings, there are no sentient beings, nor their affairs and principles. This is one point. Secondly, sentient beings have their own karmic conditions and karmic forces for suffering; when the conditions have not yet arrived, rescue is useless, and one can only watch as sentient beings drift in the ocean of birth and death, bobbing up and down. Only when the conditions ripen can one reach out to save them.