Mm. I remembered that kind of thing. Seems like I used to be an exorcist, from a family of priestesses. You can bless a sword to bring good fortune in battle, preserve the sharpness of the edge, and protect the blade's durability -- in physical use, but also to help protect it if you're using spiritual techniques.
Ah, it also makes it more effective against ghosts and demons and that kind of thing, but we don't really get a lot of that here.