Psalms 102:13

But what have you heard about Jerusalem in the Psalms? "For its stones are dear to your servants; its very dust moves them to pity," "You," it says, "will arise and have compassion on Zion, for it is time to show favor to it." When the time came for God to show mercy, the Lamb came. What kind of Lamb is it whom the wolves fear? What kind of Lamb is it who, though killed, kills the lion? For the devil has been called a lion, going about and roaring, seeking someone to devour; by the Lamb's blood the lion has been conquered. Behold the spectacles of Christians!

"Thou shalt arise, and have mercy upon Sion: for it is time that Thou have mercy upon her" [Psalm 102:13]. What time? "But when the fulness of time was come, God sent forth His Son, made of a woman, made under the Law." And where is Sion? "To redeem them that were under the Law." First then were the Jews: for thence were the Apostles, thence those more than five hundred brethren, thence that later multitude, who had but one heart and one soul toward God. Therefore, "the time is come." What time? "Behold, now is the accepted time: behold, now is the day of salvation." Who saith this? That Servant of God, that Builder, who said, "Ye are God's building."

You, rising up, will have mercy on Sion. From this little verse it is manifest that this psalm is spoken in the person of Sion, and not in the person of the prophet. Now Sion is she who is set upon a watchtower, and looks out upon the things which come from afar. This Sion therefore, who is set on high and on a lofty place, has fallen. Therefore 'let him who stands take heed lest he fall.' Because it is the time to have mercy on her, because the time has come. Either it is the time of mercy on account of penance, or it signifies according to the coming of the Savior. Let him therefore be confident who does penance, since the time of salvation has come: for the Lord is merciful.