That quote is about Mimara seeing herself as holy, and a tapestry depicting this that she saw years (decades?) ago.
That the tapestry is old, ancient even, seems to be implied heavily. This might be some overlooked evidence of that one liner “all prophesies must be followed. Even the false ones.” (or whatever the exact quote is).
Though admittedly, as Woden says, if it was a recent production, that brings a lot of questions. But, until someone can confirm or deny that this is new, I find it unlikely. Is this the first mention of the tapestry, or does it appear elsewhere prior to this?
Mimara is a unique character, and explaining her away as another one of Kellhus’ pawns is a huge mistake (imo). She is, I might remind everyone, one of only two POVs in the entire series to be written in present tense. Mimara throughout all her scenes, and the couple paragraphs of Yatwer herself which are easy to overlook. Something extraordinary and unusual is going on with her, and while most people are focused on Kellhus because he’s the big shiny coin to look at, Mimara’s mysteries remain largely unexplored. Maybe there’s just too much obfuscation there for anyone to figure her out though *shrug*