Rank, authority and holiness were expressed in antiquity by fringes on garments
In the book of Numbers, the Lord speaks to the Israelites through his servant Moses and commands them to wear tassels (or tsitsit) on the corners of their garments. The tassels must include a blue thread.
The Biblical passage reads as follows-
“The Lord spoke to Moses, saying- Speak to the Israelite people and instruct them to make for themselves tassels (tsitsit) on the corners of their garments throughout the generations; let them attach a cord of blue to the tassel at each corner. That shall be your tassel; look at it [the blue cord] and recall all the commandments of the Lord and observe them, so that you do not follow your heart and your eyes in your lustful urge. Thus you shall be reminded to observe all my commandments and to be holy to your God. I am the Lord your God, who brought you out of the land of Egypt to be your God- I the Lord your God.”
Numbers 15-37–41.
The tassels were in fact extensions of the hem, as we learn from innumerable illustrations in ancient Near Eastern art.
To understand the significance of the tassel, we must first understand the significance of the hem. The hem of an ancient Near Eastern garment was not simply a fold sewed to prevent the threads of the cloth from unraveling. The hem of the outer garment or robe made an important social statement. It was usually the most ornate part of the garment. And the more important the individual, the more elaborate and the more ornate was the embroidery on the hem of his or her outer robe. The tassel must be understood as an extension of such a hem.
Read the rest of Of Hems and Tassels in the online Biblical Archaeology Society Library.