Calvin's Commentaries, Vol. 4: Harmony of the Law, Part II, tr. by John King, [1847-50], at sacred-texts.com
Exod. 20:24, 25
24. An altar of earth thou shalt make unto me, and shalt sacrifice thereon thy burnt offerings, and thy peace offerings, thy sheep, and thine oxen: in all places where I record my name I will come unto thee, and I will bless thee.
24. Altare terreum facies mihi, et sacrificabis super illud holocausta tua, et sacrificia prosperitatum tuarum, pecudes tuas, et armenta tua: in onmi loco in quo memoriam posuero nominis mei, veniam ad te, et benedicam tibi.
25. And if thou wilt make me an altar of stone, thou shalt not build it of hewn stone: for if thou lift up thy tool upon it, thou hast polluted it.
25. Quod si altare ex lapidibus feceris mihi, non aedificabis eos excisos, si gladium tuum elevaveris super illos, pollues.
24. An altar of earth thou shalt make. This precept differs from the other, which I have just explained; because although it refers to the choice of a place, 111 yet the mention of a place is omitted, and it only touches upon the material and form of the altar. God, therefore, commands that an altar should be built to Him, either of earth or of a heap of stones, which had not been artificially polished. But I understand this of the altars, which either in the desert or elsewhere should be built, before the choice of the perpetual place had been manifested to them. God would have them built of earth, that they might fall down of themselves, and that no trace of them might remain after the departure of the people; but if stones were used, He forbade their being fitted together in a permanent structure, but would have them thrown rough and unpolished into a heap, lest their appearance should entice posterity to superstition. I am surprised that commentators 112 should here put themselves to the pains of inventing allegories; since God had no other object than to remove stumbling-blocks, whereby the Israelites might be turned away from the sanctuary; for we know how antiquity, and the example of our forefathers, is apt to attract the minds of the vulgar. If anything in the shape of an altar had remained, immediately religious notions would have been associated with it, that, God could nowhere be more solemnly or better worshipped, than in the place already dedicated of old by their fathers. Thus degenerate modes of worship would have sprung up, and the dignity of the sanctuary would have been brought into contempt. Wherefore this evil is anticipated when He forbids altars to be built which might exist for any length of time; and only allows them to be adapted for present use, being made of earth, or of an unfashioned heap of stones. As to “the sacrifices of prosperities,". I have elsewhere stated why I so translate the word שלומים, shelumim, 113 which signifies all prosperous and happy results; for the rendering of others, viz., peaceful things, (pacifica), is very unsuitable. The latter part of the verse, “in all places, where I record my name, I will come unto thee,” has been ignorantly perverted by commentators, and hence has afforded a ground of error; for they have read it in connection with the former part, as if God had forbidden such an altar to be made in Mount Sion also; whereas He rather anticipates a doubt, which might have otherwise perplexed the minds of the people; Will not God be favorable to us where He heard the prayers of our fathers? He replies, I say, to this by the promise, that they will pray to Him well and duly, if they only obey His command, and seek no other place except that which He shall choose. On this score it is said, that wheresoever it shall please God that sacrifices should be offered, there He will descend to you, to be favorable unto you.
“D’autant qu’il ne traitte pas expressement du lieu mais de la matiere, et forme de l’autel;” because it does not treat expressly of the place, but of the matter and form of the altar. — Fr.
In the Gloss. Ord, there is an exposition from Gregory, that “to make an altar of earth is to found our hopes upon the Incarnation of Christ; for our offering is then accepted by God, when our humility bases our works upon faith in the incarnation of our Lord;” and from Isidore, that “hewn stones are those who break the unity of the Church, and sever themselves from the society of their brethren. These Christ does not receive into His body, which the construction of the altar represents," etc.
שלמיך A.V., peace-offerings. C. says rightly that the word שלומים comprehends every kind of prosperity and happy result; but the word in the text is the pl. of שלם. — W. See Note on Numbers 10:10, ante, p. 105.