Up front: I am not a lawyer; my knowledge comes solely from reading about this topic in for-a-lay-audience sources. The following is my understanding, and in any event I think a reasonable way to handle things here.
Fair Use protects certain forms of copyright infringement, for particular purposes. One of those is educational, which this site can reasonably lay a claim to providing.
But Fair Use covers only using as much of the copyrighted material as you need in order to accomplish whatever protected goal you are seeking. So it is only Fair Use if your use of the material is necessary to accomplish your protected goal.
Ultimately, the only real way to test any particular claim of Fair Use is to get sued, go to court, and argue the use before a judge. There are a number of criteria that have to be weighed and considered, for example the length of your quotation vs. the length of the publication quoted from, the importance of every aspect of the quotation to your stated goals, and so on. Some of this is heavily subjective and comes down a lot to how well the respective lawyers argue their cases.
So in general, we should generally strive to keep quotations to a minimum for their goal. On the other hand, Fair Use is protected, and for a reason—we should not harm any question or answer for the sake of being over-stringent about this. If you have a real reason to quote the entire spell, then the entire spell should stay. Ultimately, a single spell is a very small portion of a given publication, which would make it easier to defend in court if it came to that, but obviously it won’t. Really blatant cases of copyright infringement that exceed any Fair Use rationale would have long since violated our own site guidelines on scope and question or answer length—such a massive quote suggests that the question is well past Too Broad.
The only real concern I would have for copyright infringement—linking to infringing sites, which do reproduce all or nearly-all of publications—is already handled by another Meta discussion, and is not allowed.