If we say that the individual omitted the mitzva of white strings and fulfilled only the mitzva of sky-blue strings, how is this possible? According to the opinion of Rabbi Yehuda HaNasi, the absence of either one prevents fulfillment of the mitzva with the other, and therefore in this case one would not fulfill any mitzva at all.

The Gemara answers that Rav Yehuda said that Rav said: It means that he omitted a mitzva but nevertheless performed a mitzva. And what does it mean that he omitted a mitzva? It means that he did not perform the mitzva in the optimal manner because he did not insert the white strings first, but he did fulfill the mitzva of ritual fringes.

The Gemara asks: This works out well with regard to the mishna’s statement that absence of the white strings does not prevent fulfillment of the mitzva with the sky-blue strings, which has been interpreted to mean that failing to insert the white strings before the sky-blue strings does not invalidate the ritual fringes. But what is the meaning of the mishna’s statement that the absence of sky-blue strings does not prevent fulfillment of the mitzva with the white strings?

Rami bar Ḥama said: That statement of the mishna is necessary only in the case of a garment that consists entirely of sky-blue wool. In such a case, one is supposed to insert the sky-blue strings before the white strings.

The Gemara notes that this was also stated by amora’im: Levi said to Shmuel: Aryokh, do not sit on your feet until you explain to me this matter: When the mishna states that the absence of the sky-blue strings does not prevent fulfillment of the mitzva of ritual fringes with the white strings, and the absence of white strings does not prevent fulfillment of the mitzva with the sky-blue strings, what does it mean? Shmuel said to Levi: That statement is necessary only in the case of a linen cloak on which one places ritual fringes, where there is a mitzva to insert the white strings first.

What is the reason for this? The verse states: “And they shall put on the fringe of the corner a sky-blue thread” (Numbers 15:38). “The fringe of the corner” is a reference to the string that is the same type as the corner of the garment. In the case of a linen cloak, which is generally white, this is a reference to the white strings, and since the verse mentions “the fringe of the corner” before the sky-blue thread, the white strings must be inserted before the sky-blue strings. The mishna therefore teaches that if one inserted the sky-blue strings before the white strings, we have no problem with it after the fact, and the ritual fringes are valid.

The Gemara asks: This works out well with regard to the mishna’s statement that absence of the white strings does not prevent fulfillment of the mitzva with the sky-blue strings. But what is the meaning of the mishna’s statement that the absence of sky-blue strings does not prevent fulfillment of the mitzva with the white strings?

Rami bar Ḥama said to him: That statement of the mishna is necessary only in the case of a garment that consists entirely of sky-blue wool, where it is a mitzva to insert the sky-blue strings first, as the phrase: “The fringe of the corner” indicates that the first strings one inserts into the garment are those that are the same type as the corner of the garment. The mishna therefore teaches that if one inserted the white strings first, we have no problem with it after the fact, and the ritual fringes are fit.

Rava said: Is it actually the color of the garment that determines the proper order in which one should insert the strings? Rather, Rava said: The ruling of the mishna is necessary only for a case of severed strings. The mishna teaches that if the sky-blue strings were severed and the white ones remain, or if the white strings were severed and the sky-blue strings remain, we have no problem with it, and the ritual fringes are fit.

As the sons of Rabbi Ḥiyya say: Severed white or sky-blue strings are fit, and similarly, severed hyssop branches are fit for sprinkling the water of purification mixed with the ashes of a red heifer. The Gemara asks: What measure do severed strings need to be in order to remain fit? Bar Hamduri says that Shmuel says: The strings must remain long enough to tie them in a slipknot.

A dilemma was raised before the Sages: When Shmuel says that severed strings must still be long enough to tie them in a slipknot, does that mean to tie all of the strings together in a slipknot? Or perhaps the strings may be even shorter, provided that they are long enough to tie each one individually. The Gemara concludes: The dilemma shall stand unresolved.

Rav Ashi asks: If the strings are thick and cannot be tied in a slipknot, but if they were the same length but thin they could be tied in a slipknot, what is their status? Rav Aḥa, son of Rava, said to Rav Ashi: If the strings are long enough to be fit if they are thin, all the more so they are fit if they are thick, as the mitzva one fulfills with them is more recognizable with thicker strings.

The Gemara cited the opinion of Rabbi Yehuda HaNasi, who holds that one cannot fulfill the mitzva of ritual fringes without both white and sky-blue strings, and the Gemara explained that the mishna can be interpreted in accordance with his opinion. The Gemara now asks: Who is the tanna who disagrees with Rabbi Yehuda HaNasi and holds that the sky-blue strings and the white strings are not interdependent? The Gemara answers: It is this following tanna, as it is taught in a baraita: Rabbi Yitzḥak says in the name of Rabbi Natan, who said in the name of Rabbi Yosei HaGelili, who said in the name of Rabbi Yoḥanan ben Nuri: If one does not have sky-blue strings, he nevertheless affixes white strings.

Rava said: Learn from the sons of Rabbi Ḥiyya that one is required to tie a knot after each and every set of windings, and one cannot suffice with only one knot at the end of all the windings. As, if it enters your mind to say that one is not required to tie a knot after each set of windings, then that which the sons of Rabbi Ḥiyya say: Severed white or sky-blue strings are fit, and similarly, severed hyssop branches are fit, is difficult: Once the uppermost knot is undone, all of the windings on the entire corner will come undone, as there are no other knots holding the windings in place, and in that case the garment will not have valid ritual fringes.