Charles Ellicott Commentary Numbers 15:38

"Speak unto the children of Israel, and bid them that they make them fringes in the borders of their garments throughout their generations, and that they put upon the fringe of each border a cord of blue:" — Numbers 15:38 (ASV)

That they make them fringes ... — Better, That they make them tassels on the corners of their garments throughout their generations, and that they put upon the tassel of the corner (i.e., on each tassel) a thread (or cord) of blue. The tassels (zirith) appear to be the same as the gedilim (fringes) of Deuteronomy 22:12.

The outer garment of the Jews was a four-cornered cloth, which was also used by the poor as a covering (Exodus 22:26–27). It appears to have been commonly used with a hole in the centre, through which the head was put, so that one-half covered the front and the other the back of the body.

These tassels, or fringes (Septuagint κράσπεδα —craspeda), were enlarged by the Pharisees to exhibit their punctilious fulfilment of the Law (Matthew 13:5). Great sanctity was attached to these fringes or tassels, and for this reason the woman with the issue of blood desired to touch a kraspedon of our Saviour’s garment (Matthew 9:20).