The Gemara rejects this proof: Perhaps the sons of Rabbi Ḥiyya were referring to a case where one tied knots between the sets of windings even though there is no obligation to do so.

And Rabba says: Learn from it that the uppermost knot in the ritual fringes is required by Torah law. As, if it enters your mind to say that it is by rabbinic law, whereas by Torah law it is sufficient to merely insert the strings into the hole without tying any knots, for what reason was it necessary for the Torah to permit placing wool ritual fringes on a linen cloak? It is obvious that it is permitted, since if one attaches a swatch of wool and a swatch of linen with a single connection, it is not considered a connection with regard to the prohibition against wearing a garment that includes both wool and linen. Rather, learn from it that the uppermost knot is required by Torah law.

§ Rabba bar Rav Adda says that Rav Adda says that Rav says: If a string was severed at its base, i.e., where it is connected to the garment, the ritual fringes are unfit. Rav Naḥman sat in the study hall and stated this halakha. Rava raised an objection to Rav Naḥman from a baraita: In what case is this statement said, i.e., that there is a minimum length required for the strings? That is only when the strings are initially affixed to the garment. But in the end, i.e., after the strings are affixed in an acceptable manner, its remainder and its severed strings are fit at any length.

The Gemara clarifies: What is its remainder and what are its severed strings? What, is it not that when the baraita mentions its remainder it is referring to a case where parts of the strings were severed and parts of them remain, and when the baraita mentions its severed strings it is referring to a case where the strings were completely severed, and nevertheless the strings are fit for the mitzva?

The Gemara responds to Rava’s objection: No, the tanna of the baraita is teaching one halakha, and the baraita should be understood as follows: The remainder of its severed strings are fit at any length. The Gemara asks: If so, let the baraita simply say: Its severed strings are fit at any length; why do I need the mention of its remainder? This teaches us that we require a remainder of its severed strings long enough to wrap them around the other strings and tie them in a slipknot.

§ Rabba sat in the study hall and said in the name of Rav: The string used for winding around the other strings is counted in the quota of ritual fringes, i.e., it is one of the eight strings on each corner, and there is no need to have an additional string for winding. Rav Yosef said to Rabba: Shmuel said it, and not Rav. This was also stated by another amora: Rabba bar bar Ḥana says: Rabbi Yoshiya of Usha told me that the string used for winding around the other strings is counted in the quota of ritual fringes.

Rava sat in the study hall and said in the name of Shmuel: If one wound the majority of the white and the sky-blue strings instead of leaving the larger portion of the strings hanging loose beyond the windings, the ritual fringes are nevertheless fit. Rav Yosef said to Rava: Rav said it, and not Shmuel. The Gemara supports Rav Yosef’s version from that which was also stated: Rav Huna bar Yehuda says that Rav Sheshet says that Rav Yirmeya bar Abba says that Rav says: If one wound the majority of the white and the sky-blue strings, the ritual fringes are nevertheless fit.

Rav Ḥiyya, son of Rav Natan, teaches this discussion like this: Rav Huna says that Rav Sheshet says that Rav Yirmeya bar Abba says that Rav says: If one wound the majority of the white and the sky-blue strings, the ritual fringes are nevertheless fit. And even if he wound only one set of windings, the ritual fringes are fit. But the finest way to affix the white and sky-blue strings is to ensure that one-third of the length of the strings is windings and two-thirds are loose hanging strings.

The Gemara asks: And what is the measure of a set of windings? It is taught in a baraita that Rabbi Yehuda HaNasi says: It is such that one winds once and winds a second and third time, i.e., each set must contain at least three windings. It was taught: One who minimizes the sets of windings may not have fewer than seven sets, and one who adds to this number of sets may not have more than thirteen sets of windings.

The Gemara provides explanations for these guidelines: One who minimizes the sets of windings may not wind fewer than seven sets, corresponding to the seven firmaments. And one who adds to this number of sets may not wind more than thirteen sets of windings, corresponding to the seven firmaments and the six air spaces between them.

It was taught: When one begins to form the windings, he begins winding with a white string. This is because the verse indicates that one first inserts “the fringe of the corner” (Numbers 15:38), i.e., the white strings, which are of the same type as the corner of the garment. And when he concludes the windings, he concludes with a white string, in accordance with the principle: One elevates to a higher level in matters of sanctity and does not downgrade.

§ The Gemara relates: Rav and Rabba bar bar Ḥana were sitting together. A certain man was passing by wearing a cloak that was made entirely of sky-blue wool, on which he had affixed white and sky-blue strings,