33 Hear thou another thing also: “for God shall save Sion”. He restores His Church, the faithful Gentiles He does incorporate with His Only-Begotten; He beguiles not them that believe in Him of the reward of His promise. “For God shall save Sion; and there shall be built the cities of Juda.” These same are the Churches. Let no one say, when shall it come to pass that there be built the cities of Juda? O that you would acknowledge the Edifice, and be a living stone, that you might enter into Her. Even now the cities of Juda are being built. For Juda is interpreted confession. By confession of humility there are being built the cities of Juda: in order that there may remain without the proud, who blush to confess. “For God shall save Sion.” What Sion? Hear in the following words: “and the seed of His servants shall possess Her, and they that love His name shall dwell therein”....
Source: The Enarrations, or Expositions, on the Psalms (New Advent)