Is wearing Tzitzit an obligation?

"The Gemara in Masechet Pesachim (113b) states that there are seven kinds of individuals that are excommunicated in Heaven and among them is one who does not don Tefillin on his arm and head, tie tzitzit to his garment, and place a Mezuzah on his doorpost. The Tosafot (ibid.) write that it seems that one must purchase a garment to tie tzitzit onto so as to obligate one’s self in the Mitzvah of tzitzit, just as we find in the Gemara in Masechet Sotah (14a) that Moshe Rabbeinu longed to enter Eretz Yisrael in order to be able to perform the Mitzvot that are specific to the land of Israel."

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