Kommentar zu Schemot 20:21

מזבח אדמה AN ALTAR OF EARTH [SHALT THOU MAKE] — i. e. an altar attached to the earth, meaning, that they should not build an altar upon columnes or upon a base but it must rest upon the actual ground. Another explanation is, that one should fill the hollow interior of the copper altar (Exodus 27:8) with earth at the time when they encamp, and then erect it for the purpose of sacrifice (Mekhilta d'Rabbi Yishmael 20:21:1).

AN ALTAR OF EARTH THOU SHALT MAKE UNTO ME. Rabbi Abraham ibn Ezra explained that He is saying: “Ye shall not make with Me gods of silver, or gods of gold⁵⁶⁵Verse 20. to receive power from heavenly creatures through them, that they be intermediaries between Me and you, for in every place where I cause My Name to be mentioned I — I in My Glory — will come unto thee and bless thee.⁵⁷⁶Verse 21. You have no need at all for an intermediary.” And according to the opinion of the Rabbis concerning [the verses here, i.e., that they speak of] the altars that were made in the Tabernacle and in the Sanctuary,⁵⁷¹Mechilta on the verse here. He mentioned the commandment of the altars of earth and of stones⁵⁷⁷Verse 22. in order to say that they also make the altars for G-d alone and that there they shall sacrifice the burnt-offerings and the peace-offerings, and not to the demons in the open field.⁵⁷⁸Leviticus 17:5-7. In every place where they will mention His Name, He will come upon them in His Glory to make His Divine Presence dwell among them and to bless them.

מזבח אדמה תעשה לי, you do not need to build elaborate temples for Me either, using precious materials. It suffices if you will erect an earthen altar. I am available to be prayed to and to respond.