31:21 And it shall come to pass, when many evils and troubles are befallen them, that this song shall {l} testify against them as a witness; for it shall not be forgotten out of the mouths of their seed: for I know their imagination which they go about, even now, before I have brought them into the land which I sware.
(l) That these evils are come upon them, because they have forsaken me.
31:21 Their imaginations - Inclinations to Idolatry, which they do not check, as they ought; and some of them do not only cherish it in their hearts, but as far as they can and dare, secretly practise it, as may be gathered from Amos 5:25 Acts 7:43.
31:14-22 Moses and Joshua attended the Divine Majesty at the door of the tabernacle. Moses is told again that he must shortly die; even those who are most ready and willing to die, need to be often reminded of its coming. The Lord tells Moses, that, after his death, the covenant he had taken so much pains to make between Israel and their God, would certainly be broken. Israel would forsake Him; then God would forsake Israel. Justly does he cast those off who so unjustly cast him off. Moses is directed to deliver them a song, which should remain a standing testimony for God, as faithful to them in giving them warning, and against them, as persons false to themselves in not taking the warning. The word of God is a discerner of the thoughts and intents of men's hearts, and meets them by reproofs and correction. Ministers who preach the word, know not the imaginations of men; but God, whose word it is, knows perfectly.
