I heard in the name of the Chasam Sofer that the first mitzvah of a bar mitzvah boy is that of simcha (happiness). Does anyone know where I could find the original source of this?
I searched Google and found the following quote here:
The Chasam Sofer (1762-1839) writes “the very first mitzvah one should be fulfilled by a bar mitzvah boy upon his reaching his 13th year is to rejoice and be happy to accept the mitzvahs of Hashem; for being b’simcha is a positive mitzvah in the Torah, i.e., to serve with joyousness and good-heartedness emanating from all the goodness which has been bestowed upon you.”
the author of Chidushei HaRim zt”l explained simply: The mitzvah of kerias shema is the first mitzvah incumbent on a boy when he becomes an adult on the evening of his bar-mitzvah. It is therefore clear why Rebbe opened tractate Brachos with this mitzvah.
– DanF Jun 23 '14 at 19:12