It is written: "Speak to the children of Israel and they shall make for themselves tzitzis on the corners of their garments throughout their generations )לדורותם(, and they shall place upon the tzitzis of the corner a thread of blue. And it shall be to you for tzitzis, and you shall see it and remember all the commandments of Hashem."
There are several observations here: Why is tzitzis mentioned three times? After all, it is obvious that we are dealing with tzitzis, so why did the text need to repeat over and over again that the threads on the corners are called tzitzis?
It should also be noted that the structure of these verses closely resembles the structure of the verses concerning the observance of Shabbos in Parashas Ki Sisa. There it says: "And Bnei Yisrael shall observe the Shabbos, to make the Shabbos throughout their generations )לדורותם as an everlasting covenant. Between Me and Bnei Yisrael it is a sign forever, for in six days Hashem made the heavens and the earth, and on the seventh day He rested )שבת(and was refreshed" (Shemos 31:16–17). There too, Shabbos is mentioned three times, and there too the concept of "throughout their generations” is emphasized. What do tzitzis and Shabbos have in common in that both are mentioned three times and both involve an observance "throughout the generations"?
It seems to me that the reason both tzitzis and Shabbos are mentioned three times in their respective parashiyos is to hint at the three Avos (Patriarchs), in the spirit of “A threefold cord is not quickly broken” (Koheles 4:12). For through the observance of these two mitzvos, we possess an enduring bond with Hashem, a strong connection capable of lasting throughout the generations. All the generations remain connected to Hashem through the mystery of the "threefold cord that cannot be severed."
And this is the meaning of "throughout their generations": to create an unbroken chain between Israel throughout its generations and Hashem. This is the great os (sign) borne by the Jewish nation, identifying them as belonging to Hashem. There is the os of Shabbos that binds them to Hashem, and there is os of tzitzis, the os of “ur'issem oso", "You shall see it' and remember all the mitzvos of Hashem," so that one never forgets Hashem and His mitzvos. Despite the length of the exile and all the tribulations we endure from generation to generation, we remain connected to Hashem. And this is the sign produced by tzitzis, an unforgettable sign, in the spirit of: "And you shall remember... so that you shall remember..."
It seems possible to suggest by way of homiletic wordplay that in the words: "And you shall see “oso” (“it”) the word oso may be understood as “os shelo” (“His sign”),” the sign of Hashem, namely, the tzitzis He gave us so that we remain connected to Him, just as Shabbos connects us to Him through: “Between Me and Bnei Yisrael it is an os forever.”
When I presented these ideas to the renowned gaon and author of Shu't Daas Yisrael, Rabbi Yisrael Schwartz shlita, he was delighted by them and immediately brought support from the words of the Sages cited in Daas Zekeinim MiBaalei HaTosafos (Bamidbar 15:32): "Why was the section of the wood-gatherer (“mekoshesh”) juxtaposed to the section of tzitzis? Because when the wood-gatherer desecrated Shabbos, Moshe said before Hakadosh Baruch Hu: 'Master of the Universe, it is written regarding tefillin, “so that the Torah of Hashem shall be in your mouth," yet You commanded that tefillin not be worn on Shabbos. Had he been wearing them, he would have remembered and would not have desecrated Shabbos!' Hakadosh Baruch Hu replied: 'I shall establish and command them a mitzvah through which they will remember the mitzvos just as through tefillin, and it will apply on Shabbos as well.' This is the mitzvah of tzitzis."
