It says in Medrash Rabba (Teruma 35) that Moshe got the same Sechar as Betzalel for building the Mishkan because “one who causes the Mitzva to be done gets the same Sechar as the one who does it”.
However, I remember hearing that one who facilitates the Mitzva being done gets MORE Sechar than the doer. To make matters worse, on the opposite extreme, it says in Kiddushin that the one should do a Mitzva oneself rather than sending a messenger and Rashi says that involving oneself with his body gets more Sechar.
So how does it work? Should one do Mitzvos by oneself, send a messenger, aid other’s in doing Mitzvos? What’s the best thing to get the most reward?
Interesting question. I would venture to say that there is a difference between when the person can do the mitzva himself, but he doesn’t, then there is a charge against him. This is because his not doing the mitzva exhibited a degree of lazinwess and laxity. We see this by Avrohom, that although he got Yishmael to help him serve his guest, the Midrash says that the mitzva wasn’t complete because of it. On the other hand, when a person is in a situation where he can’t do the mitzva such as when there is a need to raise money for tzedakah, and the gabbai doesn’t have that amount of money on his own. So when he gets others to do the mitzva, it is considered as if he himself did it. Regarding Moshe and Betzalel, Hashem specifically said that Betzalel was to fashion the vessels of the Mishkan, therefore Moshe couldn’t have done it, however since he helped him and taught him how to do it, so he gets credit for it also.
regarding what you heard about getting more credit than the person who did it, I would have to see this inside in order to comment on it