Rosh Hashanah 33B

בקטן שהגיע לחינוך, כאן בקטן שלא הגיע לחינוך.

in the first clause, the baraita is dealing with a minor who has reached the age of training in mitzvot. This child is taught to sound the shofar, as one is obligated to teach him the proper way to perform mitzvot. However, here, in the second clause, the baraita is dealing with a minor who has not yet reached the age of training. Although one need not prevent this child from sounding the shofar, one does not encourage him to do so.

והמתעסק לא יצא. הא תוקע לשיר ⁠— יצא. לימא מסייע ליה לרבא, דאמר רבא: התוקע לשיר ⁠— יצא. דלמא תוקע לשיר ⁠— נמי מתעסק קרי ליה.

§ The Mishnah taught: One who acts unawares while sounding the shofar, without any intention to produce a sound, has not fulfilled his obligation. The Talmud infers: One who sounds a shofar for music, even if he has no intention to perform the mitzva, has fulfilled his obligation. The Talmud asks: Let us say that the Mishnah supports the opinion of Rava, as Rava said: One who sounds a shofar for music has fulfilled his obligation. The Talmud rejects this suggestion. There is no clear proof from here, as perhaps one who sounds a shofar for music is also called one who acts unawares. It is possible that the tanna of the Mishnah includes in this category anyone who sounds the shofar without a clear intention to fulfill the mitzva.

והשומע מן המתעסק ⁠— לא יצא. אבל השומע מן המשמיע לעצמו, מאי? יצא. לימא תיהוי תיובתיה דרבי זירא, דאמר ליה רבי זירא לשמעיה: איכוון ותקע לי!

§ The Mishnah continues. And one who hears the shofar blasts from one who acts unawares has not fulfilled his obligation. The Talmud asks: However, one who hears the shofar blasts from one who is sounding the shofar for himself, without intention of sounding it for others, what is the halakha? The Mishnah apparently indicates that he has fulfilled his obligation. Let us say that this is a conclusive refutation of the opinion of R' Zeira, as R' Zeira said to his attendant: Have the intention to sound the shofar on my behalf and sound it for me. This statement indicates that one must have the intention to enable the one who hears it to fulfill his obligation.