Catechism of the Catholic Church

761 The gathering together of the People of God began at the moment when sin destroyed the communion of men with God, and that of men among themselves. The gathering together of the Church is, as it were, God's reaction to the chaos provoked by sin. This reunification is achieved secretly in the heart of all peoples: "In every nation anyone who fears him and does what is right is acceptable" to God. ¹⁵⁶

762 The remote preparation for this gathering together of the People of God begins when he calls Abraham and promises that he will become the father of a great people. ¹⁵⁷ Its immediate preparation begins with Israel's election as the People of God. By this election, Israel is to be the sign of the future gathering of All nations. ¹⁵⁸ But the prophets accuse Israel of breaking the covenant and behaving like a prostitute. They announce a new and eternal covenant. "Christ instituted this New Covenant." ¹⁵⁹