The Enarrations, or Expositions, on the Psalms

^21. “That the name of the Lord may be declared in Sion”. For at first, when the fettered were appointed unto death, the Church was oppressed: since these tribulations the Name of the Lord has been declared in Sion, with great freedom, in the Church herself. For she is Sion: not that one spot, at first proud, afterwards taken captive; but the Sion whose shadow was that Sion, which signifies a watchtower; because when placed in the flesh, we see into the things before us, extending ourselves not to the present which is now, but to the future. Thus it is a watchtower: for every watcher gazes far. Places where guards are set, are termed watchtowers: these are set on rocks, on mountains, in trees, that a wider prospect may be commanded from a higher eminence. Sion therefore is a watchtower, the Church is a watchtower....If therefore the Church be a watchtower, the Name of the Lord is already declared there. Not the Lord's Name only is declared in that Sion, but “His praise,” He says, “in Jerusalem.”