Rosh Hashanah 18A

כאן קודם גזר דין, כאן לאחר גזר דין! הכא נמי ביחיד.

Here the verse is referring to the time before one’s sentence is issued, when God shows favor and forgives; and there the verse is referring to the time after the sentence has been issued, when He no longer forgives. This implies that after a sentence has been issued, there is no possibility of repentance, which seems to contradict the statement of R' Yoḥanan. The Talmud answers: Here too it is referring to an individual, but a community is granted forgiveness even after its sentence has been issued.

וגזר דין דיחיד תנאי היא. דתניא, היה רבי מאיר אומר: שנים שעלו למטה וחוליין שוה, וכן שנים שעלו לגרדום לידון ודינן שוה. זה ירד וזה לא ירד, זה ניצל וזה לא ניצל.

§ The question of whether or not an individual’s sentence can be rescinded is a dispute between tanna’im, as it is taught in a baraita that R' Meir would say: Two people take to their beds, and their illness is the same, or two people ascend to the tribunal [gardom] for judgment, and their potential sentence is the same; but this one comes down from his bed, while that one does not come down from his bed, and this one is saved from death, while that one is not saved.

מפני מה זה ירד וזה לא ירד, זה ניצל וזה לא ניצל? זה התפלל ונענה, וזה התפלל ולא נענה. מפני מה זה נענה וזה לא נענה? זה התפלל תפלה שלימה ⁠— נענה, וזה לא התפלל תפלה שלימה ⁠— לא נענה

For what reason did this one recover and come down from his bed, while that one did not recover and come down from his bed; and why was this one saved from death, while that one was not saved? The difference between them is that this one prayed and was answered, while that one prayed, but was not answered. And for what reason was this one answered and that one not answered? This one prayed a prayer with his whole heart and consequently was answered, while that one did not pray a prayer with his whole heart and therefore was not answered.