RAV KOOK ON Shlach Part 2: The Third Passage of Shema

Every evening and morning, we say the Shema, Judaism’s supreme declaration of monotheistic faith. In the first passage, we accept upon ourselves the yoke of God’s sovereignty. And in the second, we accept God’s commandments. Interestingly, the Sages added a third paragraph to the Shema — the passage commanding us to wear tzitzit (tassels) on the corners of our garments (Num. 15:37-41). Why did they decide to add this particular paragraph, out of the entire Torah, to the central prayer of Judaism?