Charles Ellicott Commentary Deuteronomy 28:63

"And it shall come to pass, that, as Jehovah rejoiced over you to do you good, and to multiply you, so Jehovah will rejoice over you to cause you to perish, and to destroy you; and ye shall be plucked from off the land whither thou goest in to possess it." — Deuteronomy 28:63 (ASV)

As the Lord rejoiced over you. —See on Deuteronomy 30:9.