Midrash su Giobbe 25:5

"At the opening of the tent" (Gen. 18:1). You have made a good opening for passersby. You have made a good opening for strangers/converts. For were it not for you, I would not have created heaven and earth, as it is said (Isa. 40:22]), "Stretched them out like a tent to dwell in." For were it not for you, I would not have made the orb of the sun, as it is said (Ps. 19:5), "He placed in them a tent for the sun." For were it not for you, I would not have made the moon, as it is said (Job 25:5), "Even the moon is not bright [ya'ahil]." R' Levi said, In the future, Avraham will be sitting at the entrance to Gehinnom, and he will not allow a circumcised Jew to go down into it. And those who have sinned too much, what does he/He do to them? He removes the foreskin from babies who have died before they were circumcised, places it on them, and causes them to go down to Gehinnom. Thus it is said (Ps. 55:21), "He harmed his ally, he broke his pact." "In the heat of the day" (Gen. 18:1). When that day comes about which is written (Mal. 3:19), "For lo! That day is at hand, burning like an oven." "In the heat of the day." R' Yishmael taught, "In the heat of the day," this refers to six hours of the day [noon]. So then how do I interpret (Ex. 16:21), "when the sun grew hot, it would melt"? To four hours. You say four hours; might it not be six hours? When it says, "In the heat of the day," this refers to six hours. Or maybe it's the reverse -- "In the heat of the day" to four hours, and "when the sun grew hot" to six hours. You would say, how can you interpret "In the heat of the day" as four hours? Isn't it the case that, at four hours, there is heat only in a spot where the sun shines. At four hours, in the shade it is cool, and in the sun it is hot; at six hours, in the shade and the sun alike are hot. Thus you should not go by the latter version, but rather by the former: "In the heat of the day" is six hours, and "when the sun grew hot" is four hours, and only in a spot where the sun shone would it melt. R' Tanhuma said, at a time when people do not have shadows underneath [Yerush: omits "underneath"; Maharzu emends to "except underneath"]. R' Yanai said, He opened a fissure from Gehinnom and boiled the entire world, and its inhabitants to boot, for a brief moment; the Holy One, Blessed be He, said, the righteous ones are in distress, and the world is at ease? [From] this you say that heat is good for wounds.