Shema as a Love Story
The three paragraphs of the Shema can be interpreted allegorically by connecting each of the three paragraphs to a different stage of a growing, loving relationship.
"What is the love of God that is appropriate? It is to love God with an exceedingly strong love until one's soul is tied to the love of God. One should be in a continuous rapture, like a person who is 'lovesick,' whose thoughts cannot turn from his love for a particular woman. He is preoccupied with her at all times, whether he is sitting or standing, whether he is eating or drinking. Even more intense should the love of God be in the hearts of those who love him, possessing them always as we are commanded 'with all your heart and with all your soul' (Deuteronomy 6:5). This is what Solomon expressed allegorically 'for I am sick with love' (Song of Songs 2:5), and indeed, the entire Song of Songs is a parable for this concept."—Maimonides, Laws of Repentance, 10:3
Although Maimonides adapts the language of the first paragraph of the Shema (Deuteronomy 6:4-8), known as v'ahavta--תבהאו, "and you shall love"--he is clearly echoing the language of the first paragraph. "When you sit in your house, when you walk on the way, when you lie down and when you rise up" (6:7).
When one falls in love, this is what it is like. The object of one's love is all there is; the love and the relationship create a complete unity of experience. A person in love wants to shout out "Do you hear! I am in love! This is the one!" That's not too far from "Hear, O Israel, the Lord is our God, the Lord is one!" When one falls in love, one wants to learn everything about that person ("and you shall speak of them"), the conversations last all day and even through the night ("when you lie down and when you rise up").
Sometimes people exchange personal items--it used to be a sweater or a pin or a handkerchief--which they keep with them in order to be tied to that person even when outside of the beloved's physical presence. This, of course, recalls the tefillin, the leather boxes and straps that are worn each morning during prayers, but which, in earlier times, were worn by some pious Jews all day long. And photographs serve like mezuzot, the physical reminders of God with the words of the Shema, inside boxes placed on doorposts. When one first discovers God, when authentic spirituality is experienced, one is entirely enraptured by it, as one is when one first falls in love.
After one falls in love, a relationship moves into a more serious mode. The initial rapture of infatuation moves toward learning about each other, really listening to each other, creating rules for the relationship, including general ones (such as, "Don't have this kind of relationship with anyone else") and specific ones (such as, "Don't talk about my nose"). As long as the rules are observed, the relationship flourishes. When the rules are not observed, the ties that connect seem less bountiful, the relationship withers and falls apart.