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Siman 19 . The correct time for [reciting the] Blessing over the Tzitzis

19.1: The Mitzvah of Tzitzis is a personal duty (1) and not one that rests on the garment: so that as long as one does not wear the garment (2) it is exempt from Tzitzis. Therefore, there is no blessing [recited] (3) on making the Tzitzis because the Mitzvah is only fulfilled (4) when wearing the garment.

MB 1: And not one that rests on the garment - Look earlier in Section 17 MB5. [The MB explains that it is a personal duty in the sense that if one wants to wear a 4 cornered garment then one must put Tzitzis on it. However, it is not a personal duty to go and buy a 4 cornered garment in order to be able to put Tzitzis on it.]

MB 2: It is exempt from Tzitzis - Although it is written (Bamidbar 15 Verse 38) "And they shall make Tzitzis on the corners of their garments" (which implies that the duty rests on the garment), nevertheless, there is another verse (Devarim 22 Verse 12) "You shall make fringes on the four corners of your garment WITH WHICH YOU COVER YOURSELF" which means precisely when you wear it.

MB 3: On making the Tzitzis - meaning on hanging the Tzitzis on the garment, but later when he wraps himself with it he should recite the Blessing ..L'hisatef Ba'tzitzis (to wrap oneself with Tzitzis). If the Tzitzis snapped after he put on the garment, he must take it off, make [new] Tzitzis and make another Blessing when he puts it back on even though he puts it back on straight away.

MB 4: When wearing the garment - The same applies to a Mezuza, which also is a duty on the resident [rather than on the residence] so one only recites the Blessing on the [Mitzvah of] Mezuza when one first moves in to the house - that is the exact parallel to the wrapping [of the Tallis] (but not when one buys it). Alternatively, [one can say the Blessing] when one has been living in it (perhaps this means after settling in).

19.2: If one made a garment specifically for using for shrouds (for the dead) (5) it is exempt from Tzitzis even if he sometimes wears it during his lifetime.

MB 5: It is exempt from Tzitzis - The Later Authorities conclude that [this ruling] is specifically according to R' Osher [the Rosh] who, earlier in Section 18, rules that 'Night Clothes' (ie clothes generally worn only at night) are exempt [from Tzitzis] even if [one occasionally wears them] during the day: shrouds are similar to 'Night Clothes' in that a dead man is exempt from wearing Tzitzis. However, Rambam, who rules that 'Night clothes' worn during the day require Tzitzis would also rule that shrouds [worn prior to death] require Tzitzis. Therefore, according to us, (See Ramoh - Section 18:1) one should attach tzitzis [to these shrouds] but not make a Blessing [on wearing them]. Salesmen, who wear clothes in order to demonstrate the size & fitting (models), are exempt [from putting Tzitzis on these garments]. However, clothes worn merely to evade a tax/levy may be obliged [to have Tzitzis], similar to [the prohibition] of Shaatnez (that applies in this case).