Midrash sa Malakias 3:20: Ein Yaakov (Glick Edition), Kohelet Rabbah, Ruth Rabbah & Mekhilta DeRabbi Yishmael

(Ib. b) R. Chanina said in the name of R. Myashia, who quoted R. Juda b. Eliah: "What does the passage (Mal. 3, 20) But unto you, that fear My name, shall the sun arise, mean? This refers to men who are afraid to mention the name of the Lord in vain." Shall the sun of righteousness arise, with healing in its wings. Said Abaye: "We infer from this that the sunbeams are healing to sickness." This will differ with the opinion of R. Simon b. Lakish, who said: "There is no Gehenna in the future world, but the Holy One, praised be He! — will bring forth the sun from its sheath, with which the righteous will be cured and the wicked will be punished; as it is said (Mal. 3, 19) For, behold, the day cometh it burneth as a furnace; and all the proud, and all that work wickedness, shall be stubble; and the day that cometh shall set them ablaze, saith the Lord of Hosts, that it shall leave them neither root nor branches."

R. Isaac said: "Even in a year of drought, as were the years of Elijah, if rain fall on the Sabbath eve, it can only be considered as a sign of calamity." This significance [is attached to the occurrence also by] Rabba b. Shila, who said: "A rainy day is hard as the day of judgment [because it prevents people from pursuing their vocations]," Amemar said: "Had it not been for its necessity to the world, I would pray His mercy to abolish it." Further R. Isaac said: "Sunshine on the Sabbath is a generosity for the poor; as it is said (Malachi 3, 20) But, there shall be rise unto you that fear my name the sun of righteousness with healing in its wings." Again said R. Isaac: "Great is the day of rain, for then even the coin in one's pocket is blessed; for it is said (Deut. 28, 12) To give the rain of thy land in its season, and to bless all the work of thy hand." R. Isaac said again: "Heavenly blessing does not occur but in things which are hidden from the eyesight [the exact quantity of which is not known]; as it is said (Deut. 28, 8) The Lord will command upon thee the blessing in thy storehouses [where the exact quantity is unknown]." In the college of R. Ishmael it was taught: "Heavenly blessings will not be frequent except upon things of which no eye can look." Our Rabbis were taught: "He who is about to measure the grain in his barn, should say: 'May it be Thy will, O Lord, our God, that Thou shalt send blessing to the labor of our hands.' When he begins to measure off, he should say: 'Praised be He Who sendeth blessings upon this heap.' If, however, he prayed after measuring, his prayer is in vain, because [heavenly] blessing is not frequent on things which are weighed, measured or counted, but on things which are hidden from the eyesight; as it is said: The Lord will command upon thee the blessing in they storehouses [where the exact quantity is unknown]."

It is taught in the name of Rabbi Natan: The sphere of the sun has a pouch; that is what is written: “He set a tent for the sun in them” (Psalms 19:5). There is a pool of water before it. When [the sun] seeks to emerge, it becomes enflamed, and the Holy One blessed be He weakens its strength with water so it will not incinerate the world. But in the future, the Holy One blessed be He will strip it from its pouch, expose it, and incinerate the wicked with it, as it is stated: “For, behold, the day is coming, burning like a furnace, [and all the criminals and all those who do evil will be straw; the day that is coming will burn them]” (Malachi 3:19). Rabbi Yannai and Rabbi Yishmael, both of them say: There is no Gehenna in the future; rather, the sun will emerge. The righteous will benefit from it. From where [is this derived]? It is as it is stated: “It will rise for those who fear My name, a sun of righteousness with healing in its wings” (Malachi 3:20). And the wicked will be punished with it, as it is stated: “The day that is coming will incinerate them” (Malachi 3:19).