Adapted from an article by Rabbi Sasson Yaakov
The Gemara states that the seven types of people who are excommunicated in Heaven include he who does not lay tefillin on his arm and head, tie tzitzit on his garment and place a mezuzah on his doorpost (Pesachim 113b). The Tosafot (ibid.) writes that therefore it appears one is obligated to buy a tallit katan (i.e. a garment to tie tzitzit onto so as to obligate one’s self in the mitzvah of tzitzit), just as we find in the Gemara in (Sotah 14a) that Moshe Rabbeinu longed to enter Eretz Yisrael in order to be able to perform the mitzvahs that are only observed in the Land of Israel.
The Gemara recounts that when an angel met Rav Ketina and saw him wrapping himself in a tallit that was exempt from tzitzit (i.e. because it did not have four corners, like typical garments of his era), the angel rebuked him and said, “What shall be with the mitzvah of tzitzit?” (Menachot 41a).
Rav Ketina replied, “Do you exact punishment even for not performing a positive commandment in a passive way as well?”
“Indeed,” replied the angel, “in time of wrath and day of reckoning, we punish even for abstaining from performing a positive mitzvah.”
The Mordechai writes that only when one has a four-cornered garment but seeks ways to exempt himself from this mitzvah – such as rounding off one of the corners – is he punished for this, just as the angel told Rav Ketina that at a time of heavenly wrath, one is punished for abstaining from performing positive mitzvahs.
This applied during Rav Katina’s time, when people were accustomed to wearing four-cornered garments, but today, since we are unaccustomed to wearing four-cornered garments, there is no punishment at all if one does not observe the mitzvah of tzitzit, and even during a time of wrath one will not be punished for this. Nonetheless, it is best to procure a four-cornered garment in order to fulfill the mitzvah of tzitzit (Chapter 541).
Based on the above, it is clear that according to the opinion of the Mordechai, there is no actual obligation to wear a tallit katan with tzitzit, for the punishment mentioned in the Gemara only applies when one already possesses such a garment and tries to exempt himself from this mitzvah by behaving in an untoward manner. Today, since most of our garments are not four-cornered, there is no obligation to make a special effort to wear a four-cornered garment in order to obligate one’s self in the mitzvah of tzitzit.
Similarly, the Rambam writes: “Although one is not obligated to purchase a four-cornered garment a wrap himself in it in order to tie tzitzit onto it, nevertheless, it is not fitting for a pious individual to exempt himself from this great mitzvah; rather, one should always try to be wrapped with a garment that is obligated in tzitzit so as to fulfill this mitzvah. One should be extra careful with the mitzvah of tzitzit during prayer, for it is a great degradation for a Torah scholar to pray without being wrapped in a tallit. One should always be careful regarding the mitzvah of tzitzit for the Torah equates this mitzvah to be as great as all the other mitzvot, as the verse states, ‘And you shall see it and you shall remember all of the mitzvot of Hashem and you shall perform them’” (Hilchot Tzitzit, Chapter 3, Halacha 11).
The Tur and Shulchan Aruch (Chapter 24) rule likewise.
The Gemara expounds the verse “Your clothing shall be white at all times” to refer to the mitzvah of tzitzit (Shabbat 153a), and the Talmud Yerushalmi states that one who is meticulous regarding this Mitzvah shall merit greeting Hashem’s holy presence (Berachot Chapter 1, Halacha 2).
The Sefer Chassidim (written by Rabbeinu Yehuda Hachassid, one of the greatest earlier Rishonim) recounts that a certain individual had a dream that a deceased man came and told him should confess, for he would soon die. The man fasted after every dream, and during the dream, he would recite the Psalm of “By David, to you, Hashem, do I raise my soul” and then recite the entire Vidduy (confession) in tears. He became deathly ill and saw before him a cloud in the form of a person carrying a load and holding a gold coin, and the form of another man wrapped in a tallit. He said, “In the merit of your wrapping yourself in a tallit and the gold coin that you gave to a poor Torah scholar, you have been redeemed from death and you shall live.” He broke into a sweat and was healed.
Though there is no obligation to wear a tallit katan in order to obligate one’s self in the mitzvah of tzitzit, nevertheless, it is very proper and fitting for every man try to fulfill this cherished mitzvah, which is equated to all other mitzvahs, by wearing a tallit katan under one’s clothing all day.
It is also proper to teach children to keep this mitzvah by dressing them with a tallit katan. According to Eliyah Rabba, a boy should wear a tallit katan from the age of three and by doing so he will merit having a lofty soul.
Article used with permission from Halacha Yomit