Deuteronomy 28:63
And it shall come to pass, that as the LORD rejoiced over you to do you good, and to multiply you; so the LORD will rejoice over you to destroy you, and to bring you to nought; and ye shall be plucked from off the land whither thou goest to possess it.
The chapter containing the verse sets forth plainly the blessings of obedience as God's law, giving the principles of the law of His kingdom made specific so that minds are not left in ignorance and uncertainty, with the call to keep His statutes and heed His voice. Its words are the voice of Christ from the enfolding pillar of cloud, expressing the never-ceasing obligation of all who are blessed with life and health and temporal and spiritual advantages. The message has not grown weak with age, but God's claims are just as binding now and as fresh in importance as His gifts are fresh and continual, and Christ has repeated these directions with His own voice, calling His followers to a life of consecration and self-denial.
The good and multiplication promised were conditional on observing to do all the words of the law written in the book and fearing the glorious and fearful name, so that God alters His purpose toward the people according to their course. He sends prosperity when they obey His law and adversity and curse when they transgress it, doing them good and multiplying them in obedience and bringing destruction and removal from the land He gave them in disobedience. The verse thus sets the fearful consequences of transgressing God's commands against the blessings of obedience, so that people must choose whether to suffer those consequences or enjoy those blessings. Mere possession of the ark did not itself guarantee success, for the dealing was always upon condition of obedience.
The verse teaches the reversal of blessing for disobedience: as the Lord rejoiced over the people to do them good and to multiply them, so He will rejoice over them to destroy them and bring them to nothing, plucking them from off the land they go to possess. This is part of the curses Moses read to Israel for breaking the law, belonging to the warning that persistent transgression brings loss of blessing and removal from the land. The reversal leaves them few in number after plagues and long sicknesses and diseases, plucks them from the land and scatters them among all people from one end of the earth to the other to serve other gods, with trembling heart and failing eyes and sorrow of mind and a fearful, uncertain life. The destruction and scattering from the land of promise came through transgression in introducing strange gods by means of evil spirits, leading to eventual removal from the land.
The chapter gives these directions as God's law and as practical warnings for the people's present and future good. Its warnings apply to Israel's final overthrow and to the destruction of Jerusalem by Rome. God's conditional dealing was seen in His refusal to bring the adult generation that left Egypt into the promised land when they disobeyed.