Wyjścia 30:14 Midrasz: Midrash Tanchuma

And thou shalt make an altar to burn incense (Exod. 30:1). What do the letters in the word ketoret (“incense”) stand for? The kuf stands for kedushah (“sanctification”), tet for taharah (“purity”), resh for rahamim (“mercy”), and ta for tikvah (“hope”). A cubit shall be the length thereof, and a cubit the breadth thereof; and two cubits shall be the height thereof (ibid.). What was the purpose of this altar? After they committed the act of erecting the golden calf, the Holy One, blessed be He, complied with his (Moses’) request, as is said: And the Lord repented of the evil (ibid., v. 14). Whereupon Moses said: Master of the Universe, You have already agreed with me (to forgive them), but who will make known to those who come unto the world that You are reconciled with Israel? He replied: Let them make Me a Sanctuary, that I may dwell among them (Exod. 25:8), and let them offer sacrifices within it, and I will accept their lamb.