A command to wear tassels is found in just two places in the Bible.

Num 15:38  “Speak to the children of Israel: Tell them to make tassels on the corners of their garments throughout their generations, and to put a blue thread in the tassels of the corners.
Num 15:39  And you shall have the tassel, that you may look upon it and remember all the commandments of the LORD and do them, and that you may not follow the harlotry to which your own heart and your own eyes are inclined,
Num 15:40  and that you may remember and do all My commandments, and be holy for your God.

Deu 22:12  “You shall make tassels on the four corners of the clothing with which you cover yourself.

What is this law all about?  Does God want Christians to wear tassels?  Let’s take a closer look. 

God gives the reason for wearing tassels with the command for wearing them.  The tassels were to remind the people to remember the commandments of the LORD and do them, and not follow the harlotry to which they were inclined, Num 15:39.  The real commandment here is to remember the commandments of the LORD and do them.  The tassels were just an aid.

The context can also help in our understanding.  There is not much in the way of context surrounding Num 15:38-40; it stands out on its own.  However, Deu 22:12 is set after various commandments relating to agriculture, which were again to remind the Israelites to be separate from the pagan nations and not to partake of the ways of the pagan world in any shape or form.  For more information on this see, ‘What does “You shall not wear a garment of mixed linen and wool” mean?’

In speaking of the new covenant, which Christians are under, God said He will put His law in our minds and write it on our hearts.

Jer 31:31  “Behold, the days are coming, says the LORD, when I will make a new covenant with the house of Israel and with the house of Judah—
Jer 31:32  not according to the covenant that I made with their fathers in the day that I took them by the hand to lead them out of the land of Egypt, My covenant which they broke, though I was a husband to them, says the LORD.
Jer 31:33  But this is the covenant that I will make with the house of Israel after those days, says the LORD: I will put My law in their minds, and write it on their hearts; and I will be their God, and they shall be My people.

The purpose of wearing tassels is to remind us of God’s law.  But Christians don’t need reminding, because under the new covenant they have God’s law in their hearts and minds.  Therefore there is no need to wear tassels, although there is no harm in doing so.