Lectures on the Sūtra of the Collection of the Father and Son (Pitāputrasamāgamanasūtra) (81)

However, the Buddha said that at the time of the extinction of the life faculty at the end of dying—that is, when our lifespan comes to an end, when we are about to die but have not yet died, which is called the time of the extinction of the life faculty—one thing occurs: the Buddha said that one's own karmic retribution all manifests. What is one's own karmic retribution? It is the retribution of the karmic actions one has personally created manifesting, just like waking from a dream and knowing what one did in the dream. Before we die at the end of life, everything we have done in this life, whether wholesome or unwholesome, appears in the mind as swiftly as a film being played, and we know what we have done throughout this life, whether there has been more wholesomeness or more unwholesomeness, what kind of retribution we should receive, and into which realm of saṃsāra we should be reborn.

Pondering this over and over, one feels it strange in the mind: when karma was being created, it was done without anyone knowing, and the karmic actions have already ceased to exist, yet at the end of life they all manifest. Why can they all manifest? Because when karmic actions are being performed, each action, moment by moment, is stored as seeds in the tathāgatagarbha; the actions cease to exist, but the seeds remain. Actions have form and appearance and can cease to exist, whereas seeds are formless and without appearance, and they do not cease to exist until the retribution has been received. When sentient beings reach the end of life, they then know whether their wholesome karma or unwholesome karma in this life was greater, into which realm they should go to receive retribution, and according to which karma they should receive retribution—all is perfectly clear in the mind, but they can no longer speak. The karmic actions of cause and effect are truly inconceivable.