Jews in antiquity, like orthodox Jewish people today, wore tassels, or "tzitzit," on the edges of their robes as a demonstration of their faith. There were a number of reasons for this. In the book of Numbers in the Old Testament, it is stated that Jews should "make tassels on the corners of their garments throughout the generations." This directive is given again in Deuteronomy, where the tassels are specifically called "twisted cords."
The wearing of these tassels was therefore a way for Jews to show their dedication to God and to their faith. It also was (and remains) a means of displaying their faith to others. There are particular methods for tying the tassels, and the most observant Jews would tie the tassels exactly as described in the Torah.