I've heard people say that attending a Siyum gets the merit like you learned all of the Gemara that's getting Siyum'd on.
Is there a mekor (Torah source) for this idea?
(And if yes, then does any Sefer explain that it's not exactly the same reward? It's hard for me to understand that the partaker gets the same full reward as the person that spent 100's of hours working on the Gemara.)
Thank you for any help regarding this