מדרש אויף איוב 19:18

[2] Another interpretation: "And the Lord remembered Sarah" (Genesis 21:1). This means that just as it says "And He will not forsake you, nor destroy you" (Deuteronomy 13:18) and "He will give you compassion and have compassion on you" (Deuteronomy 13:18), Moses said to the people of Israel, "May you have a sign in your hand: Whenever you have compassion for your fellow human being, the Holy One, blessed be He, also has compassion on you. If you do not have compassion for your fellow human being, the Holy One, blessed be He, will not have compassion on you." Likewise, every time Job used to say that his friends were against him and his friends used to say that he was wrong, justice was intensified. As it says, "And now they mock me, those who are younger than I, whose fathers I disdained to put with my sheep dogs" (Job 30:1), and "And even the little boys scorn me; when I arise, they speak against me" (Job 19:18). However, as soon as he prayed for his friends, the Lord answered him, as it says, "And the Lord restored Job's losses when he prayed for his friends" (Job 42:10). When did this happen? When he prayed for his friends. Similarly, whenever Abimelech had a conflict with Abraham, he suffered. As it says, "For the Lord had closed up all the wombs of the house of Abimelech because of Sarah, Abraham's wife" (Genesis 20:18). But as soon as Abraham prayed for him, both of them were accepted, as it says, "And Abraham prayed to God, and God healed Abimelech, his wife, and his maid servants, and they bore children" (Genesis 20:17). And what is written after that? "And the Lord remembered Sarah."