At one time the Buddha was staying near Nālandā in Pāvārika’s mango grove.

Then the householder Upāli went up to the Buddha … and asked him, “What is the cause, sir, what is the reason why some sentient beings aren’t fully extinguished in the present life? What is the cause, sir, what is the reason why some sentient beings are fully extinguished in the present life?” …

(This should be told in full as in SN 35.124.)