This mitzvah of tzitzit is the equivalent of all the mitzvot combined. -- Talmud Menachot 43b.
Whoever observes the mitzvah of tzitzit meticulously will be found worthy of beholding the Divine Presence. -- ibid.
Rabbi Eliezer ben Yaakov said: He who has tefillin on his head and arm, tzitzit fringes on his garment, and a mezuzah on his doorway, presumably will not sin. As it is stated (Ecclesiastes 4:12), "a three-stranded cord will not quickly be broken." -- ibid.
One who meticulously observes the mitzvah of tzitzit is rewarded with [the resources to afford] a nice wardrobe. -- Talmud Shabbat 23b.
"This is my G-d and I will beautify Him" (Exodus 15:2). Be beautiful before him with mitzvot ... a beautiful tallit. -- Talmud Shabbat 133b.
A Torah scholar must be proficient in the laws of tzitzit. -- Talmud Chulin 9a.
G-d told Abraham: "You told the king of Sodom, 'Neither from a thread to a shoe strap, nor will I take from whatever is yours' (Genesis 14:23). I swear that as a reward I will give your children the mitzvah of the tzitzit thread." -- Midrash Rabbah Genesis 43:13.
"The L-rd desires for the sake of Israel's righteousness to make the Torah great and glorious" (Isaiah 42:21). G-d did not leave anything in His world which does not involve a mitzvah for Israel. Humans wear clothing, so G-d commanded to attach tzitzit to their garments. -- Midrash Rabbah Numbers 17:7.
Whoever observes the mitzvah of tzitzit, regarding him it is said (Zechariah 8:23): "In those days, when ten men of all the languages of the nations shall take hold of the corners of the garment of a Jewish man, saying, 'Let us go with you, for we have heard that G-d is with you.'" -- Sifri Numbers 115.
The numerical value of the word tzitzit is 600, with eight strings and five knots -- this equals 613, the amount of the commandments of the Torah. -- Pesikta Zutreta Shelach.
Whoever observes the mitzvah of tzitzit, it is considered as if he has observed the entire Torah. -- ibid.
Said Rabbi Shimon bar Yochai: When a person rises in the morning and dons the tefillin and tzitzit ... the Divine Presence dwells upon this person and proclaims: "You are My servant, Israel, in whom I will be glorified!" -- Zohar Chadash, Terumah 41d.
With the tzitzit, as with the brass snake, "every one that is bitten, when he sees it he shall live." -- Zohar III 175a.
Halachapedia on Tzitzit
Daily Daf on Tzitzit Fabrics
Star-K on Tzitzit Kashrut
Aish on Tzitzit
Chabad Tzitzit Resources
Book: Laws of Tzitzis