When should we repeat a statement of a theorem before proof in a paper?
Unless, you are facing a particular nasty page limit, those few lines spent repeating the theorem should not be a concern to you. Thus, the only concern you should have is what benefits the reader. Here, redundancy is not bad as such, but only if it annoys the reader and wastes their time. Therefore, you have to compromise between the following:


Readers whom the redundant information helps. In most cases, you have to expect that readers have not memorised the entire theorem yet, and this is clearly information that is relevant to reading the proof. Of course, readers can flip back to the theorem, but that’s a major annoyance (even if you can put the pages next to each other).

Even if the theorem equals the title of your paper and is something like:


  Every frasmotic contrafibularity is a compunctuous pericobobulation.


and you spend the entirety of the space between first stating the theorem and proving it with talking about the four terms involved, you cannot expect the reader to remember that, e.g., Theorem 2 was this titular theorem. Even if you refer to it as titular theorem, readers may need more time to understand this than to read the short theorem again.
Readers who are annoyed by the repetition. – In the situation you describe, I would expect that only very few readers do not need the theorem repeated to them. If the formatting is any reasonable, those should notice very quickly that you are restating the theorem so they can skip it.


Therefore, in most cases (including the one you describe), I would conclude that for the average reader the usefulness of restating the theorem outweighs the annoyance.