Musar על תענית 54:16

Our sages have taught that anyone who nowadays studies the details of the sacrificial service in the Temple, is as if he had actually offered those sacrifices (Menachot 110). When someone observes that a second party is able to perform a certain מצוה that he himself is unable to perform, the "preparation," הכנה, that we described includes his advising the second party how best to fulfill such מצוה which he himself is unable to perform. If he does that, he too will be considered as if he had performed it.