Matthew Henry Commentary Deuteronomy 27:1-10

"And Moses and the elders of Israel commanded the people, saying, Keep all the commandment which I command you this day. And it shall be on the day when ye shall pass over the Jordan unto the land which Jehovah thy God giveth thee, that thou shalt set thee up great stones, and plaster them with plaster: and thou shalt write upon them all the words of this law, when thou art passed over; that thou mayest go in unto the land which Jehovah thy God giveth thee, a land flowing with milk and honey, as Jehovah, the God of thy fathers, hath promised thee. And it shall be, when ye are passed over the Jordan, that ye shall set up these stones, which I command you this day, in mount Ebal, and thou shalt plaster them with plaster. And there shalt thou build an altar unto Jehovah thy God, an altar of stones: thou shalt lift up no iron [tool] upon them. Thou shalt build the altar of Jehovah thy God of unhewn stones; and thou shalt offer burnt-offerings thereon unto Jehovah thy God: and thou shalt sacrifice peace-offerings, and shalt eat there; and thou shalt rejoice before Jehovah thy God. And thou shalt write upon the stones all the words of this law very plainly. And Moses and the priests the Levites spake unto all Israel, saying, Keep silence, and hearken, O Israel: this day thou art become the people of Jehovah thy God. Thou shalt therefore obey the voice of Jehovah thy God, and do his commandments and his statutes, which I command thee this day." — Deuteronomy 27:1-10 (ASV)

As soon as they had come into Canaan, they were to set up a monument, on which they were to write the words of this law. They were to set up an altar. The word and prayer must go together. Although they were not allowed, on their own initiative, to set up any altar besides the one at the tabernacle, yet, by God's appointment, they could do so on special occasions.

This altar was to be made of unhewn stones, such as they found in 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 by God the Father, and made the Head of the corner. In the Old Testament, the words of the law are written with the accompanying curse, which would overcome us with horror if we did not have, in the New Testament, an altar erected close by that gives consolation.

Blessed be God, the printed copies of the Scriptures among us remove the necessity for such methods as were prescribed for Israel. The purpose of the gospel ministry is, and the purpose of preachers ought to be, to make the word of God as plain as possible. Yet, unless the Spirit of God prosper such labors with Divine power, we will not, even by these means, be made wise for salvation. Therefore, we should daily and earnestly pray for this blessing.