TT #2 · Parashas Toldos · Passuk 25:21
Yitzchak pleaded with Hashem on behalf of his wife, because she was infertile; and Hashem responded to his plea, and his wife Rivkah conceived.
Torah Temimah points to Yevamos 64a. E-Daf · Sefaria — Yevamos 64a
Rabbi Yitzchak asked: Why is the prayer of the righteous compared to an atar (a pitchfork)? Just as an atar turns the grain from place to place, so the prayer of the righteous turns the Holy One from the attribute of anger to the attribute of mercy.
Custom (Bavli — prayer of the righteous overturns the attribute of severity)
The prayer of the righteous is compared to a pitchfork: it turns the Divine attribute from severity to mercy.