And there shalt thou build an altar unto the LORD thy God, an altar of stones: thou shalt not lift up any {c} iron tool upon them.

(c) The altar should not be curiously wrought, because it would continue but for a time: for God would have only one altar in Judah.

Jamieson-Fausset-Brown Bible Commentary

5-10. there shalt thou build an altar . of whole stones-The stones were to be in their natural state, as if a chisel would communicate pollution to them. The stony pile was to be so large as to contain all the conditions of the covenant, so elevated as to be visible to the whole congregation of Israel; and the religious ceremonial performed on the occasion was to consist: first, of the elementary worship needed for sinful men; and secondly, of the peace offerings, or lively, social feasts, that were suited to the happy people whose God was the Lord. There were thus, the law which condemned, and the typical expiation-the two great principles of revealed religion.

Matthew Henry's Concise Commentary

27:1-10 As soon as they were come into Canaan, they must set up a monument, on which they must write the words of this law. They must set up an altar. The word and prayer must go together. Though they might not, of their own heads, set up any altar besides that at the tabernacle; yet, by the appointment of God, they might, upon special occasion. This altar must be made of unhewn stones, such as they found upon the field. Christ, our Altar, is a stone cut out of the mountain without hands, refused by the builders, as having no form or comeliness, but accepted of God the Father, and made the Head of the corner. In the Old Testament the words of the law are written, with the curse annexed; which would overcome us with horror, if we had not, in the New Testament, an altar erected close by, which gives consolation. Blessed be God, the printed copies of the Scriptures among us, do away the necessity of such methods as were presented to Israel. The end of the gospel ministry is, and the end of preachers ought to be, to make the word of God as plain as possible. Yet, unless the Spirit of God prosper such labours with Divine power, we shall not, even by these means, be made wise unto salvation: for this blessing we should therefore daily and earnestly pray.