It is appears that one is not required to wear tzitzis unless he wears a 4 cornered garment. The gemara does mention that one should wear tzitzis to keep away Divine wrath. Thus, is wearing a tallis katan Rabbinic or custom? Also, when did it originate, as it doesn't seem to be around in Talmudic times (as people put the tzitzis on the 4 cornered garments that was the custom of the times to wear)?
Barry Epstein, Dallas, USA
Wearing a Talis Katan is neithe Rabbinic nor a custom. It is the fulfillment of a Torah Mitzvah.
There are two different types of positive Mitzvos. One is obligatory (such as eating Matzah on Seder night), and the other is not obligatory, but one fulfills the Mitzvah d'Oraisa if he does it (such as eating Matzah on the remaining days of Pesach). It is a Mitzvah d'Oraisa to perform Shechitah, but one is not obligated to perform that Mitzvah unless he wants to eat meat. Similarly, one is not obligated to wear Tzitzis unless he wants to wear a four-cornered garment, in which case he must place Tzitzis on the garment.
It has always been the practice of Jews to fulfill as many Mitzvos as they can, even when they are not obligated to do so. Therefore, even when four-cornered garments went out of style, Jews continued to wear four-cornered garments (such as the Talis Katan) in order to fulfill the Mitzvah of Tzitzis.