898. Verse 12. Having a wall great and high, signifies the Word in the sense of the letter from which is the doctrine of the New Church. When the Lord's New Church as to doctrine is meant by "the holy city Jerusalem," nothing else is meant by its "wall" but the Word in the sense of the letter, from which the doctrine is; for that sense protects the spiritual sense, which lies hidden within, as the wall does a city and its inhabitants. That the sense of the letter is the basis, the containant, and the support of its spiritual sense, may be seen in The Doctrine of the New Jerusalem concerning the Sacred Scripture (n. 27-36) And that this sense is the guard, lest the interior Divine truths, which are those of the spiritual sense, should be injured (n. 97). Also that the doctrine of the church is to be drawn from the sense of the letter of the Word, and to be confirmed by it (n. 50-61). It is called "a wall great and high," because the Word is meant as to the Divine good and the Divine truth; for "great" is predicated of good, and "high" of truth, as above (n. 896).
 By "a wall" is signified that which protects; and, in speaking of the church, the Word in the sense of the letter is signified in the following passages:
I have set watchmen upon thy walls, O Jerusalem; they shall not be silent day and night, that make mention of Jehovah (Isa. 62:6).
They shall call thee the city of Jehovah, the Zion of the Holy One of Israel; and thou shalt call thy walls salvation, and thy gates praise (Isa. 60:14, 18).
Jehovah will be a wall of fire round about, and a glory in the midst of her (Zech. 2:5).
The sons of Arvad were upon thy walls, and the Gammadians hung their shields upon thy walls round about; they have made thy beauty perfect (Ezek. 27:11).
This is concerning Tyre, by which is signified the church as to knowledges of truth from the Word.
Run to and fro through the streets of Jerusalem, and see if there is any that seeketh truth; go up on her walls, and cast down (Jer. 5:1, 10).
Jehovah hath thought to destroy the wall of the daughter of Zion, He made the rampart and the wall to mourn, they languish together, the law and the prophets are no more (Lam. 2:8, 9).
They shall run to and fro in the city, they shall run on the wall, they shall go up into the houses, they shall enter in through the windows (Joel 2:9).
These are concerning the falsifications of truth:
Day and night the wicked go about in the city, upon its walls, destructions are in the midst of them (Ps. 55:10).
Besides other places, as Isa. 22:5; 56:5; Jer. 1:15; Ezek. 27:11; Lam. 2:7. That the Word in the sense of the letter is signified by "a wall," is clearly manifest from what follows in this chapter, where the wall, its gates, foundations, and measures are much treated of. The reason is, because the doctrine of the New Church, which is signified by "the city," is solely from the sense of the letter of the Word.