37. The Mitzvah of Tzitzis
9:1 The mitzvah of wearing tzitzis is very great because many other mitzvos depend upon it. The Torah tells us (Numbers 15:39) that when we look at the tzitzis, we will be reminded of God’s commandments so that we may perform them. The 613 mitzvos are alluded to by the numerical value of the word “tzitzis,” which equals 600, plus the eight threads and five knots that are on each corner. (600 + 8 + 5 = 613.) It is therefore important for each male to wear a garment called a tallis katan in order to fulfill the mitzvah of tzitzis. (This is in addition to the large tallis worn during prayer, which also has tzitzis on it.) Tzitzis should be purchased from a reputable dealer in order to ensure that they were made with the intention of fulfilling the mitzvah.
9:2 A tallis should be made of wool. If a person can only afford a linen tallis, it is problematic to put woolen tzitzis on it because of shaatnez, the prohibition of wearing wool and linen in the same garment. There is an opinion that one could make the corners of the tallis from leather and then attach the tzitzis there, but others do not permit this. The Mishnah Brurah (9:18) says that, while a wool tallis is optimal, it is better to have a tallis of other materials, even with linen strings, than to neglect the mitzvah altogether.