The parashah also has a second Shema (Deut. 4:1), “Now, O Israel, hear the statutes and judgments which I teach you to observe…”.
The double Shema gives us the two dimensions of Judaism – knowledge and practice.
Some would use the technical terms theology and ritual, but that implies a dichotomy which is not really Jewish. The preferred Jewish approach is to say that you cannot be pious without knowledge, and you cannot have knowledge without living the principles you learn.
In which way does the Shema, the more famous version about God and His oneness, teach the principle of knowledge?
When it says Shema, “listen”, it does not tell us merely to use our ears but to utilise our minds. Shema in this sense means to perceive.
That is one explanation of the rule that requires us to say the first line with special devotion and concentration. Devotion and concentration require the mind. When we say the words we have to think them. The message has to register.