'Deride' means to put down, either figuratively with criticism, or literally as in this case. 'Derision' is the more common form, like 'words of derision'. because of that last association, this word probably wouldn't be used in modern english, this must be an old fashioned text full of formal obscure old words. It's saying that that divinity breaks down the boundaries between them, and makes them one. But this is an odd old word. Most native speakers don't have any idea what 'deride' means. So in standard spoken english this pronouncement (by a priest at a wedding maybe) would be something like: "According to ancient custom, by the divine attraction of virtuous people to each other, I and the divinity in me and in them breaks down the seperation of individual egos and unites them as one." But I don't think that's neccesarily better than the original. It's nice to have flowery old language for ritual things, it's so poetic and fun.

unite, merge, combine, become one

Zooey's answer is correct.