Deuteronomy 31:19

Ver. 19. Now, therefore, write ye this song— The divine composition which follows in the next chapter has ever been admired as a master-piece; and no wonder, when we consider who was its author. It has always been thought the most profitable method of instructing people, and communicating things to posterity, by putting them into verse. For this reason, as Aristotle reports, people anciently sung their laws; and Tully tells us, that it was the custom among the ancient Romans to have the virtues and praises of their famous men sung at their feasts, as a witness against those who degenerated from the noble deeds of their ancestors, and disgraced the great examples which such poetry proposed to them, ver. 21. The 22nd verse should be read in a parenthesis; it being evident, that He, in the 23rd verse, refers to God. See Cicero, Tusc. Quaest. lib. 4. Bentley's Dissertation on the Epistles of Phalaris, p. 373 and the Memoirs of M. Delanauze upon the Songs of the Greeks, in the Royal Academy of Inscriptions, tom. 13:

REFLECTIONS.—Moses is again warned of his approaching end. The best of men need be admonished to put their house in order. Hereupon, 1. Moses is summoned to the tabernacle, with Joshua, solemnly delegated to be his successor, there to receive his charge. 2. God hereupon appears to them in the Shechinah, and foretells, [1.] The departure of Israel from him, and their adultery with idols, transgressing, as a wife, the covenant of marriage in which they had been joined to the Lord, and this, in consequence of their abuse of prosperity, and the carnality of their wicked hearts. Note. (1.) All love of sin is spiritual adultery. (2.) They, who pamper the body to inflame their lusts, will quickly seek unlawful gratifications for them. [2.] God's anger is threatened against them: since they forsake him, he will forsake them; and woe unto them, when his wisdom no longer guides, nor his power protects them! Note; The greatest bitterness of every affliction is, to have God's face turned away from us in anger.