Joshua 8:30

30.Then Joshua built an altar, etc God had been pleased that this should be the first extraordinary sacrifice offered to him in the land of Canaan, that thus the people might attest their gratitude, and the land begin to be consecrated in regular form. It was not possible for the people to do it before freely and on their own soil, till they had obtained possession of some vacant region. (77) Now, God had at the same time given them two commands — first, that they should erect an altar on Mount Ebal; and secondly, that they should set up two stones plastered over with lime, on which they should write the Law, in order that every passer by might be able to see it and read it. We now read that both were faithfully performed. A third command related to the recitation of blessings and cursings: this, too, Joshua performed with no less care.

To begin with the altar, — it is said, that according to the divine command, it was formed of unhewn stones. For entire stones on which the masons’ iron has not been employed, are called rough and unworked. (78) This is specially said in Deuteronomy 27:0, of the altar, of which mention is now made. But the same thing had before been said in general of all others. Some expounders, in searching for the reason, needlessly have recourse to allegory, and allege that the hand and industry of men are forbidden, because the moment we introduce any devices of our own, the worship of God is vitiated. This is indeed truly and wisely said, but it is out of place, as the divine intention simply was to prohibit the perpetuity of altars. For we know, that in order to sacrifice duly, it was enjoined that all should have one common altar, in order both to cherish mutual agreement, and to obviate all sources of corruption from the introduction of an adventitious superstition; in short, in order that religion might remain one and simple, as a variety of altars would soon have led to discord, thereby distracting the people and putting sincere piety to flight.

Then it was not left to the choice of the people to select a place, but God uniformly in the books of Moses claims this for himself. He therefore confines the exercises of piety to that place where he may have put the remembrance of his name. Moreover, as the divine will was not immediately manifested, nor the place designated, that worship might not in the mean time cease, it was permitted to build an altar where the ark should happen to be stationed, but an altar formed only of a rude pile of stones, or of turf, that it might be only temporary.

Let the reader observe that an option was given to the people to make it of rough stones, that its form might not attract veneration, or of earth, which would crumble away of its own accord. In one word, this arrangement tended to give a pre-eminence to the perpetual altar, after God made choice of Mount Zion for its locality. Hence it is said in the Psalm, I was glad because our feet will stand in thy courts, O Jerusalem! (Psalms 122:1) What other translators render peace offerings, I have, not without cause, rendered by sacrifices of prosperity, because they were offered up either to solicit successful results, or to render thanks; and the Hebrew term is not unsuitable, as the reader will find more fully explained in my commentaries on the books of Moses.