Isaiah 54:10 - Matthew Poole's English Annotations on the Holy Bible

The mountains shall depart, and the hills be removed; which hath been verified in some mountains and hills, that by earthquakes, or otherwise, have been removed from their places. But these kind of absolute expressions are ofttimes comparatively understood, of which See Poole on "Isaiah 51:6"; and so the sense is, The mountains shall sooner depart from their places, than my kindness shall depart from thee. As when it is said absolutely, I desired mercy, and not sacrifice, it is meant comparatively, I desired mercy more than sacrifice, as it is explained in the following clause. The covenant of my peace; that covenant whereby I have made peace and friendship with thee, and have promised unto thee all manner of happiness, which frequently comes under the name of peace in Scripture. The sense of the place is, that God will not cast off his Christian church, as he did cast off the church of the Jews; and that the new covenant is established upon better and surer promises than the old, as is observed, Hebrews 8:6,7, &c., and elsewhere. That hath mercy on thee; who doth thus with thee not for thine own merits, but merely for his own grace and mercy.