There are many frozen Falmer in the Chantry of Auriel, one of whom has a random Expert spell tome that could be one of the following:

Detect Dead

Ebonyflesh

Paralyze

Command/Expel Daedra

Conjure Dremora Lord/Storm Atronach

Dread Zombie

Icy Spear

Thunderbolt

Incinerate

Wall of Flames/Frost/Storms

Pacify

Invisibility

Rout

Circle of Protection

Grand Healing

Repel Undead

Turn Greater Undead

It's held by a Falmer/Betrayed, not one of the original inhabitants (unless the use of the same model is just gameplay); why do you think a savage Falmer would be clutching a spell tome even while freezing (probably being frozen near-instantaneously, given the poses of some of the frozen Falmer and Chaurus)? Even if the Falmer model was just due to gameplay limitations, what would one of those spell tomes be doing in, as Gelebor says, "a place of peaceful worship"? Most of those could probably be for fighting or avoiding combat with against fauna...except the anti-Undead spells and Dread Zombie (again, assuming it's not just gameplay).

Hmm, perhaps dealing with any undead that attack?

To run with it as not being simply gameplay, I remember a playthrough I really enjoyed when I started thinking about what the elven hero was like who wielded that weapon in one of the locked Paragon rooms in the Chantry. Who wielded this weapon, and why was it given such honour? It might be worth thinking about what "peaceful worship" meant to the Snow Elves. i mean, they worship a very strict god.

It's an abstract thought, but if we compare with the Dunmer and their peaceful worship with their Ordinators standing guard to remind you what an Outlander you are and ready to subject us to corporal re-education should we so much as touch the wrong relic or look at them funny, we could say the term "peaceful worship" is a cultural-centric view. That is to say, yeah they are peaceful towards other people they consider to be "people." But for everyone else, like one of those proto-Bretons or Nedes, these peaceful worshippers could well be ready to get not so peaceful rather quickly.