After the story of the spies, the last section of this parasha deals with tsitsit and is the third verse of the Shema.
Nechama Leibowitz explained that the underlying intention of Tsitsit is clarified in this parasha. She quoted from Rashi whose interpretation of the word was that it alludes to “looking”, and he wrote “the tsitsit shall be a witness that you may look upon it”. The verse in the Torah goes on to explain “And you shall see it and remember all the commandments of the Lord and do them”, as the sages say “teaching that seeing leads to remembering and remembering to doing”. She quoted from Nachmanides that the object of the seeing was the blue thread. Nachmanides and Rashbam reasoned that “blue is like the sea, the sea is like the sky, and the sky is like the throne of Glory”. The blue thread reminds man of his Creator, and his obligation to carry out His will, through the medium of the precepts of the Torah.
What if we don’t have a blue thread in our tsitsit? Sforno explained that “you will remember that you are servants of the Almighty, from whom you received commandments on oath. This you will do when you see the seal of the King on his servants.”
Ibn Ezra wrote that “this precept applies to everyone who has a four-cornered garment, that he should wear it continually and not take it off in order to remember. This is to remember not to err and sin at all times”.