21 It shall happen, when many evils and troubles are come on them, that this song shall testify before them as a witness; for it shall not be forgotten out of the mouths of their seed: for I know their imagination which they frame this day, before I have brought them into the land which I swore."
*Minor differences ignored. Grouped by changes, with first version listed as example.
This song shall testify against them - Because in it their general defection is predicted, but in such a way as to show them how to avoid the evil; and if they did not avoid the evil, and the threatened punishment should come upon them, then the song should testify against them, by showing that they had been sufficiently warned, and might have lived to God, and so escaped those disasters.
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.
And it shall come to pass, when many evils and troubles are befallen them,.... As did in the times of the judges, in the Babylonish captivity, and do now in their present exile:
that this song shall testify against them as a witness; which so clearly points at their sins, with all their aggravated circumstances, and describes so fully their calamities, distresses, and punishment for them:
for it shall not be forgotten out of the mouths of their seed; which shows that it respects time to come, their later posterity, whose memory of this song would be conjured up by the evils that should come upon them for their sins; nor is it forgotten by them to this day, who acknowledge there are some things in it now fulfilled or fulfilling in them:
for I know their imagination which they go about even now: or are "making" (c); forming and framing within themselves, there being a secret inclination in their minds to idolatry, which were working and contriving schemes to bring it about, and set it up; and this, God, the searcher of hearts, knew full well, and that in process of time this evil imagination would break forth into act, in an open and flagrant manner:
before I have brought thee into the land which I sware; to their fathers, to give it to them for an inheritance, as is suggested in Deuteronomy 31:20.
(c) "faciens", Montanus; "quam facit", Pagninus.
*More commentary available at chapter level.