Chapter 20. Regarding The Fringe (On Clothing)
4075. It was narrated that Jãbir bin Sulaim said: "I came to the - -- Prophet when he was sitting with his hands around his knees and he had put the fringe of his garment over his feet." (Da'if)
The fringes are known by the Hebrews as the term for "tassels". They are commanded in the Taurat (Torah) for the people of Israel for all future generations. They were four strings blue in colour attached to the four corners of garments. Pray shawls were also used by the Hebrews which resembled the "abayah", a blanket worn by the Bedouins for the protection from the sun and rain which has black stripes at its ends.
The biblical command comes from Numbers 15:37-41:
"Speak to the children of Israel and bid them to affix fringes (tzitziot) to the corners of their garments... that you may look upon them and remember all the commandments of the Lord."
The Prophet Muhammed claimed to have known about the Torah and Gospel. He confirmed both and so it wouldn't be unusual for him to adopt the religious practices of the Torah. All Prophets of God must confirm the Torah (Isaiah 8:14).
The practice of tassel wearing has fallen away in our age because our garments are no longer created with four corners. Many religious people buy four cornered garments so that they can keep the commandment.