Catechism of the Catholic Church

709 The Law, the sign of God's promise and covenant, ought to have governed the hearts and institutions of that people to whom Abraham's faith gave birth. "If you will obey my voice and keep my covenant, . . . you shall be to me a kingdom of priests and a holy nation." ⁷⁵ But after David, Israel gave in to the temptation of becoming a kingdom like other nations. The Kingdom, however, the object of the promise made to David, ⁷⁶ would be the work of the Holy Spirit; it would belong to the poor according to the Spirit.

710 The forgetting of the Law and the infidelity to the covenant end in death: it is the Exile, apparently the failure of the promises, which is in fact the mysterious fidelity of the Savior God and the beginning of a promised restoration, but according to the Spirit. The People of God had to suffer this purification. ⁷⁷ In God's plan, the Exile already stands in the shadow of the Cross, and the Remnant of the poor that returns from the Exile is one of the most transparent prefigurations of the Church.