Ashrei is an alphabetic acrostic, a fancy way of saying that each verse begins with letters of the Hebrew alphabet in order (aleph aromimcha, bet bechol yom, gimel gadol, etc.) But it was already noted 2000 years ago that the nun verse is missing!
Why? “Rabbi Yochanan said, “It denotes the downfall of Israel, as it is written: ‘Naflah -She has fallen and will not continue to rise, the virgin of Yisrael’ (Amos 5:2). [Berachot 4b].” The problem with this interpretation is that there are hundreds of words starting with nun that would be perfectly appropriate; and on the other hand, for every letter, there are hundreds of words that wouldn’t be appropriate!
On top of that, there are several versions of the Bible that do have a verse starting with nun in the ashrei! The Greek translation called the Septuagint, and Dead Sea Scroll fragments (11QPs-a), have the similar lines: In the Septuagint: “neeman el-kim bidvarav, v’chasid bechol maasav” “G-d is faithful to His word, and gracious in all His actions.” And in the Dead Sea Scrolls, “neeman el-kim bchol derachav, v’chasid bechol maasav” “G-d is faithful in all His ways, and gracious in all His actions.”
Now, here’s the question: was that nun line found in the original version, and then, for some reason, dropped out? Or was it omitted from the original version, and then, for some reason, added? And if it was, in fact, the original, should we perhaps reintroduce it in our prayers?
There are several stylistic reasons to think that it was a later addition, included by a pious scribe who was upset or confused by the omission. Mitchell First, a prolific Jewish scholar, points out 1) that the suggested nun verse uses the name el-kim for G-d, while all the other names of G-d in ashrei are the four letter name; 2) there is a major thematic break between the mem line (emphasizing G-d’s rule) and the samech line (emphasizing G-d’s graciousness)—omitting a nun line underscores this; 3) by omitting the nun line, the letter sequence spells out the word “king” (mem, lamed, kaf) in reverse order, and omitting the nun line underscores this; 4) the end of the suggested line is repeated in the tzadi verse, which is unlikely; and finally, 5) by omitting the nun line, we are left with 21 verses, and therefore a middle verse, verse 11 kaf: kevod machutecha yomeiru, we will speak of the honor of your kingdom, arguably the main theme of the entire psalm.
Summing up, there is more to Rabbi Yochanan’s interpretation than is seen at first glance. Regardless of the reason no nun verse was included, the fact is that thematically, the contrast between the lavish praise of G-d which is the Ashrei, and the abject horrors of exile of the fallen Israel, could not be greater. The message of the Ashrei, seen through the lens of Rabbi Yochanan’s comments, is simply this: have faith. The kingdom of G-d is sure to come. It may not seem that way now, but fallen Israel will rise because (as the next verse after the nun-space states) “somech ad-nai lchol hanoflim….” “Ad-nai supports all who have fallen, and uplifts all who are bowed down.”
Rabbi Robert L. Wolkoff