There are two descriptions of the mitzvah of tzitzis. First, from parashas Shelach (and Qeri’as Shema):
… [T]hey should make for themselves tzitzis on the corners of their garments (bigdeihem) throughout their generations, and that they put on the tzitzis of each corner a thread of blue wool (techeiles). And it shall for you tzitzis, and you will see it and remember all the mitzvos of Hashem… (Bamidbar 15:38-39).
There are a few points I want to stress about this quote:
1- The term for garment used is beged. Hebrew has a number of terms for clothing. That it’s called a beged rather than a kesus or a levush is significant. The uniform of the kohanim is called the bigdei kehunah. By saying the mitzvah is on our begadim is to cas