Charles Ellicott Commentary Isaiah 54:10

"For the mountains may depart, and the hills be removed; but my lovingkindness shall not depart from thee, neither shall my covenant of peace be removed, saith Jehovah that hath mercy on thee." — Isaiah 54:10 (ASV)

For the mountains shall depart. —Better, “may depart.” The same bold hyperbole is found in Psalms 46:3; Jeremiah 31:36; Matthew 24:35.

The covenant of my peace. —The phrase is taken from Numbers 25:12, and re-appears in Ezekiel 34:25; Ezekiel 37:26. “Peace,” as elsewhere in the Old Testament, includes nearly all that is wrapped up in the “salvation” of the New.