Midrash for Exodus 30:10

[(Exod. 30:12): WHEN YOU TAKE A CENSUS.] What is written <just> before this lection (in Exod. 30:10)? AARON SHALL MAKE ATONEMENT UPON ITS HORNS (i.e., the horns of the incense altar) <ONCE A YEAR>.¹³Tanh., Exod. 9:6; PRK 2:7. When Israel sinned, the Holy One said to Moses: Go and make atonement for them. He said to him: Sovereign of the World, did you not say this: ONCE A YEAR? The Holy One said to him: Go and restore them. R. Abbin the Levite said: Moses said to the Holy One: Sovereign of the World, out of all the peoples that you have in your world, you only charge me concerning Israel. (Lev. 20:2:) AND UNTO THE CHILDREN OF ISRAEL YOU SHALL SAY. (Exod. 30:31:) UNTO THE CHILDREN OF ISRAEL YOU SHALL SPEAK. To what is the matter comparable?¹⁴Tanh., Exod. 9:8. To a King who had purple garments.¹⁵Gk.: porphurai. Now he had a certain purple cloak which he cherished more than all of them. So he commanded his servant and said to him: Shake it out; fold it up. He also said to him: Set your mind on it. He said to him: My Lord King, of all your purple garments you have only commanded me concerning this one. He said to him: Because I wore this one when I first became king, I therefore cherish it more than all these <other> garments of mine. In such a way did the Holy One speak, when <Moses> said to him: For what reason did you command me more concerning Israel than all the <other> peoples which are in the world? He said to him: For what reason? Because they were the first to make me king, <when they did so> by the sea. (Exod. 15:18:) THE LORD SHALL REIGN FOR EVER AND EVER.

Another comment on The tongue of the righteous is as choice silver (Prov. 10:30). This refers to the Holy One, blessed be He, who chose the tongue of Moses when he told him: When thou takest the sum (to obtain forgiveness). What is written above concerning this very matter? And Aaron shall make atonement upon the horns of it once in the year (Exod. 30:10). After Israel had sinned, the Holy One, blessed be said to Moses: Go, atone for them. Whereupon Moses replied: Did You not say to me once in the year? The Holy One, blessed be He, replied: Go lift up their heads (obtain forgiveness) now. Then Moses said to the Holy One, blessed be He: Master of the Universe, when they do good let them be at rest, but when they are without merit, as though that were possible, let them be forgiven once a year in order that the Day of Atonement may come and atonement be made for them, as it is said: For on that day shall atonement be made for you (Lev. 16:30).

9) "and he shall make atonement upon it (the altar)": atonement which is (made) upon its body. (i.e., atonement through the blood, which is placed upon the corners of the altar [and not verbal atonement])."and he shall take of the blood of the bullock and of the blood of the he-goat": intermixed. I might think of each by itself; it is, therefore, written (Shemoth 30:10) "of the blood of the sin-offering of the atonement once a year." How, then, am I to understand "and he shall take of the blood of the bullock and of the blood of the he-goat"? As "intermixed." (For otherwise, it would be twice a year.)