And Moses wrote all the words of the Lord— Some have supposed that the art of writing was derived immediately from GOD himself, and shewn to Moses particularly by the writing on the tables of stone, mentioned Exodus 24:12 but it appears from hence, that Moses understood the art of writing before those tables were delivered to him; and there seem good reasons to believe, that this art had already been long in use. See note on ch. Exodus 18:6.
And builded an altar—and twelve pillars— The parties in the covenant were GOD and the people of Israel: the altar, therefore, was to be a representation of the throne of the Deity; the twelve pillars of the twelve tribes. For the rest, the usual foederal rites are observed.