Midrash su Malachia 3:17

I will make thee a terror, and thou shalt be no more refers to the present time; thou shalt be sought for, yet shalt thou never be found again refers to the Messianic Age. But Israel existed in the past, and will live in the future. Whence do we know this? It is written: Remember thy congregation which Thou has acquired of old (Ps. 74:2). Of old alludes to the time before the world was created. And they exist now, for it is said: Ye are standing this day (Deut. 29:9), But ye that did cleave unto the Lord your God are alive, every one of you this day (ibid. 4:4); that they will exist in the future is indicated in the verse And they shall be Mine, saith the Lord of hosts, in the day that I do make, even Mine own treasure; and I will spare them, as a man spareth his own son that serveth him (Mal. 3:17).

A parable: To what is this matter to be compared? To a man who had precious utensils. And he did not desire to give them as an inheritance except to his son; likewise with the Holy One, blessed be He. The day of blessing and holiness which was before Him, He did not desire to give it as an inheritance except to Israel. Know that it is so ! Come and see ! for when the Israelites went forth from Egypt, whilst yet the Torah had not been given to them, He gave them the Sabbath as an inheritance. Israel kept two Sabbaths whilst as yet the Torah had not been given to them, as it is said, "And thou madest known unto them thy holy Sabbath" (Neh. 9:14). And afterwards He gave them the Torah, as it is said, "And commandedst them commandments, and statutes, and Torah by the hand of Moses, thy servant" (ibid.).

What is written above? "And the Lord will pass over the opening." (Exodus 12:23) At that time - as if it were possible - He, Himself, stood at the opening. But rather, as it is the custom of the world - in the same way as when a butcher brings in his sheep and he takes red dye and marks each lamb and sheep that he wants to slaughter, in order to recognize which one to slaughter and which one not to slaughter; so too (Ibid.), "and he will see the blood" - as if it were possible - He stood at the entrance and pushed away the destroyer that he should not strike Israel. God said to them (Ibid. 24), "'And you shall keep this thing as a statute for you and your children forever" - in the same way as I did [this] for you today, so [too] will I do [it] for you in the future to come," as it is stated (Malachi 3:19), "As behold the day is coming, burning like a furnace, etc." "But [with] you, 'I will have pity upon you as a father has pity on his son.' (Ibid. 17)"