Yevamot 107 - 113
Studying, Doing and Teaching
- Yevamot 109b
"One who declares that he serves G-d only with his Torah study has nothing more to his credit than Torah study."
This seemingly simplistic statement of Rabbi Yossi is explained by the gemara in two radically different ways.
One approach is based on Rabbi Papa's interpretation of the passage (Devarim 5:11) "You shall learn them (the laws of the Torah) and keep and do them" as indicating that only one who acts in accordance with his learning is considered as having acquired the merit of Torah. It follows then that one who limits his service of G-d to only Torah study lacks the merit of that service as well.
Another approach is that Rabbi Yossi was addressing the fellow who teaches others to fulfill the commandment that he does not and assumes that he will be credited with their performance. According to this more generous approach he will indeed receive credit for his Torah study but not for the actual performance of the mitzvot that he expects to be credited to him.
We might add that if he does those same mitzvot as well as teaching about them he will be credited as well with the performance of his students.