Isaiah 35:7

The Lord promises concerning holy Church through another prophet, saying: "There shall spring up in her the greenness of the reed and the rush." I remember having explained this in another place, that by the reed we should understand writers, and by the rush, hearers. But since both rush and reed are accustomed to grow near the moisture of water, and both spring forth from one and the same water, and the reed indeed is taken up for writing, while with the rush one cannot write, what should we understand by the rush and the reed, except that there is one doctrine of truth which irrigates many hearers? But some who are irrigated advance in the word of God even to the point that they also become writers, that is, like reeds; but others hear the word of life, maintain the greenness of good hope and right works, yet cannot advance to writing at all. What are these in the water of God except certain rushes, so to speak? They indeed advance by growing green, but they cannot express letters at all.

But since I have not quoted to you such Scripture as tells that Christ will do these things, I must necessarily remind you of one such: from which you can understand, how that to those destitute of a knowledge of God, I mean the Gentiles, who, 'having eyes, saw not, and having a heart, understood not,' worshipping the images of wood, [how even to them] Scripture prophesied that they would renounce these [vanities], and hope in this Christ. It is thus written: 'Rejoice, thirsty wilderness: let the wilderness be glad, and blossom as the lily: the deserts of the Jordan shall both blossom and be glad: and the glory of Lebanon was given to it, and the honour of Carmel. And my people shall see the exaltation of the Lord, and the glory of God. Be strong, ye careless hands and enfeebled knees. Be comforted, ye faint in soul: be strong, fear not. Behold, our God gives, and will give, retributive judgment. He shall come and save us. Then the eyes of the blind shall be opened, and the ears of the deaf shall hear. Then the lame shall leap as an hart, and the tongue of the stammerers shall be distinct: for water has broken forth in the wilderness, and a valley in the thirsty land; and the parched ground shall become pools, and a spring of water shall [rise up] in the thirsty land.' The spring of living water which gushed forth from God in the land destitute of the knowledge of God, namely the land of the Gentiles, was this Christ, who also appeared in your nation, and healed those who were maimed, and deaf, and lame in body from their birth, causing them to leap, to hear, and to see, by His word. And having raised the dead, and causing them to live, by His deeds He compelled the men who lived at that time to recognise Him.