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2. May one who is exempt from hearing Shofar blow for others?
(Although the main Mitzvah of hearing Shofar is merely to hear the sound nevertheless) if the blower is exempt from the Mitzvah then he cannot fulfill the obligation on behalf of others through blowing for them.
A child: Even a child who has reached the age of Chinuch is unable to blow and fulfill the obligation of an adult which is Biblically obligated in the command.
 Admur 588:6; Michaber 589:1
 The Kuntrus Hashulchan states that in truth this word should read “blowing Shofar”.
 Parentheses is in original.
 This refers to one who is exempt from the Mitzvah entirely and not to one who is obligated in the Mitzvah and has already fulfilled it, in which case he can still blow Shofar for others as will be explained in Halacha 9F. [Kaf Hachaim 589:1]
The reason: Since Hashem does not desire this person himself to perform the command, how can he fulfill the command on behalf of others. [Levush 589; Kaf Hachaim 589:2]