The Bible does not command wearing of a unique prayer shawl or tallit. Instead, it presumes the people to already use an outer garment of some type to cover themselves and instructs them to add fringes (tzitzit) to the 4 corners of these (Numbers 15:38, Deuteronomy 22:12). These passages do not specify tying particular types or numbers of knots in the fringes. Nor do they specify a gender division between men and women, or between native Israelite/Hebrew people and those assimilated by them. The commandment was addressed to all adult Israelites and those of "the mixed multitude" that exited Egypt with them.
Talking About Prayer Shawls / Threshing Floor Sermon
Jewish tradition added rabbinical interpretations to provide guidance and "fence" commandments to prevent unintentional transgression by believers. Rituals for donning the garment are an example of this. They are extra-biblical observances important to Jewish worship and culture.
Encyclopaedia Judaica, Second Ed., Vol. 19, Som-Tn, 2007, describes the prayer shawl as "a rectangular mantle that looked like a blanket and was worn by men in ancient times." Also, it "is usually white and made either of wool, cotton, or silk." "Strictly observant Jews prefer tallitot made of coarse, half-bleached lamb's wool."
A few decades ago, the horizontal stripes which run across the narrow ends of the shawl were exclusively black. They are now available in colors including: blue, maroon, white, purple, gold, silver, rainbow, pink, and combinations of colored stripes with metallic stripes.
According to the biblical commandment, a blue (Heb. תכלת , "tĕkeleth", tek·ā'·leth) thread (Heb. פתיל "pethiyl") known as "tekeleth" itself, is included in the tzitzit (Numbers 15:38). Strong's H8504 for "blue" defines the dye as obtained from the shell of a Mediterranean mussel: helix ianthina that provided a hue called cerulean purple. It is also defined as violet color, which is a shade between blue and purple.
Various methods of knotting the fringes have evolved. The important part of the tallit is the tzitzit. Tzitzit are a reminder of the 613 commandments comprising the entire code of law. The fringes themselves were commanded as a reminder not to wander from God's commandments (Numbers 15:39).