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A Shofar which one vowed against using:
If one vowed not to use a certain persons Shofar it is permitted for another person to blow with that Shofar and have him listen to the blows and fulfill his obligation. If one vowed not hear the sound of a certain Shofar then it is forbidden for him to blow even one sound with this Shofar even if he intends to fulfill his obligation. [Furthermore it is forbidden even for another person to blow using this Shofar and have him fulfill his obligation.]
Mudar Hannah-One who vowed against receiving benefit from his friend: If one vowed against receiving benefit from a certain individual it is forbidden for him to ask that individual to blow Shofar for him. Nevertheless it is permitted for that individual to blow Shofar for him on his own initiative without having been asked by the person who made the vow. The above however only applies if one forbade receiving benefit from that individual. If however he forbade hearing Shofar from that individual then it is forbidden for him to hear the blowing from that person even for the sake of fulfilling the Mitzvah.
 Michaber 586/5; This law is not found in the Alter Rebbe’s Shulchan Aruch.
 Such as he said “Konem Hanaas Shofar Alay” [Mateh Efraim 586/7; M”B 586/21]
 However he himself may not blow the Shofar being that there are a lot of people that do receive pleasure from blowing the Shofar and since one’s body receives pleasure it cannot be permitted on the basis that Mitzvos are not given to receive benefit. [Taz 586/4 based on Rif and Maor] However according to the Rambam and others [Rabbeinu Yerucham; Rosh; Tur; Aguda] it is permitted for him to blow the Shofar on the basis that Mitzvos were not given for one to receive pleasure. The Bach rules that initially one is to be stringent although if there is no one else available to blow the Shofar one may be lenient. The M”A 586/7; Mateh Efraim 586/7; M”B 586/22; Kaf Hachaim 586/40 rule like the Bach. The Peri Chadash rules like the Rambam. See 586/24 and 26 that there is no pleasure at all involved in blowing Shofar Vetzaruch Iyun.
How many times is one to blow if there is no one else available? If the person who made the vow is blowing the Shofar he may blow only ten blows of תשר“ת תש“ת תר“ת being that this is the Biblical obligation. [Mateh Efraim 586/7; M”B 586/22] This means to say that one is to blow three sets of each for a total of 30 blows, as this is the minimum amount of blows Biblically required. [Kaf Hachaim 586/40]
 Such as he said “Konem Letekiaso Alay”. [ibid]
 Mamar Mordechai 586/7; M”B 586/24
 As the hearing of Shofar is not considered a benefit. Nevertheless it is forbidden for the person to ask this friend to blow Shofar for him being that it is forbidden to make him an emissary. [ibid]