The ceremony here under Joshua was twofold: first, the rearing of an altar; and second, the proclamation of the law.
1. The altar, as enjoined in Exod. xx. 24, was of whole, undressed stones. In its simple structure it was designed to show that the Most High dwelleth not in temples made with hands. In its open position it demonstrated that the most fitting place for His worship was not the secret recesses of the woods, but the open air and full light of heaven, seeing that He is light, and in Him is no darkness at all. On this altar were offered burnt offerings and peace offerings to the Lord. The sacrificial system had been little attended to amid the movements of the wilderness, and the warlike operations in which the people had been more or less engaged ever since their entrance on the land; but now was the beginning of a more regular worship. The first transaction here performed was the sacrificial. Here sin was called to mind, and the need of propitiation. Here it was commemorated that God Himself had appointed a method of propitiation; that He had thereby signified His gracious desire to be at peace with His people; that He had not left them to sigh out, "Oh that we knew where we might find Him, that we might come even to His seat!"--but had opened to His people the gates of righteousness, that they might go in and praise the Lord.
Moreover, we read in Joshua, that "he wrote there upon the stones a copy of the law of Moses, which he wrote in the presence of the children of Israel." There is sufficient difference between the passages in Deuteronomy and Joshua to show that the one was not copied from the other. From Joshua we might suppose that it was on the stones of the altar that Joshua wrote, and there is no reference to the command given in Deuteronomy to plaister the stones with plaister. But from Deuteronomy it is plain that it was not the stones of the altar that were plaistered over, but memorial stones set up for the purpose. There has been no little controversy as to the manner in which this injunction was carried out. According to Dr. Thomson, in the "Land and the Book," the matter is very simple. The difficulty in the eyes of commentators has arisen from the idea that plaister is altogether too soft a substance to retain the impression of what is written on it. This Dr. Thomson wholly disputes: "A careful examination of Deut. xxvii. 4, 8 and Josh. viii. 30-32 will lead to the opinion that the law was written upon and in the plaister with which these pillars were coated. This could easily be done; and such writing was common in ancient times. I have seen numerous specimens of it certainly more than two thousand years old, and still as distinct as when they were first inscribed upon the plaister.... In this hot climate, where there is no frost to dissolve the cement, it will continue hard and unbroken for thousands of years,--which is certainly long enough. The cement on Solomon's pools remains in admirable preservation, though exposed to all the vicissitudes of the climate and with no protection.... What Joshua did therefore, when he erected those great stones on Mount Ebal, was merely to write _in_ the still soft cement with a style, or more likely _on_ the polished surface when dry, with red paint, as in ancient tombs. If properly sheltered, and not broken by violence, they would have remained to this day."
Joshua could not have written the whole of the law on his pillars; it was probably only the ten commandments. As we shall see, another arrangement was made for the rehearsal of the whole law; it was solemnly read out afterwards. But now the entire nation, with all the strangers and followers, took up their position in the valley between the two mountains. Half of the tribes separated from the rest to the slopes of Gerizim, and the other half to those of Ebal. From Deuteronomy we gather that those who were grouped on Gerizim were far the more important and numerous tribes. They embraced Simeon, Levi, Judah, Issachar, Joseph, and Benjamin. On Mount Ebal were stationed Reuben, Gad and Asher, Zebulun, Dan and Naphtali. The priests stood between, and read out blessings and curses. When blessings were read out the tribes on Gerizim shouted Amen. When curses were read out those on Ebal did the same. Let us imagine the scene. A mountain side covered with people is always a picturesque sight, and the effect is greatly heightened when the clothing of the multitude is of light, bright colours, as probably it was on this occasion. "It was," says Dr. Thomson, "beyond question or comparison the most august assembly the sun has ever shone upon; and I never stand in the narrow plain, with Ebal and Gerizim rising on either hand to the sky, without involuntarily recalling and reproducing the scene. I have shouted to hear the echo, and then fancied how it must have been when the loud-voiced Levites proclaimed from the naked cliffs of Ebal, 'Cursed is the man that maketh any graven image, an abomination to Jehovah.' And then the tremendous AMEN! tenfold louder from the united congregation, rising and swelling and re-echoing from Ebal to Gerizim, and from Gerizim to Ebal. AMEN! Even so, let him be accursed. No, there never was an assembly to compare with this."