Mishnah Berurah — משנה ברורה

Interweaving - Meaning, that [the threads] should be folded over after the spinning [process] into two and [then] interwoven (ie. those two threads are now spun together to make it one single, thicker thread). And if each thread was folded over into eight and interwoven as well, there is nothing [wrong with that]. And the reason for the interweaving is that it taught in the Sifri: [The verse says] "...and they shall make for themselves fringes..." (Numbers 15:38). I hear from this that they should make fringes as they are (ie. with just one thread). So the verse tells you "...let them attach a cord of blue to the fringe at each corner." (Numbers 15:38), with spinning and interweaving [meaning, like [it was done in] the Mishkan (Tabernacle) which was interwoven... Or [another interpretation] is that a cord/wick is [something that by definition is] interwoven]. Now I have no [scriptural proof for the requirement of spinning and interweaving] except for blue [fringes], how [do we know that the same thing applies to] white fringes? [Because] the Torah says "affix/place" by blue [threads] and "affix/place" by white [threads]... What [is true by] blue [threads], [that they have to be] spun and interwoven, so too [is true by] white [threads], that they have to be spun and interwoven. And see further in Biur Halacha.