"Hear O Israel, G‑d is our G‑d, G‑d is one" (Deuteronomy 6:4). The words of the Shema constitute the most basic statement of Judaism: that G‑d is our G‑d — a real presence in our lives; and that G‑d is one — the singular, absolute, all-embracing truth of our existence.

What do we do with these words? Many things.

1) Mind: We study them and contemplate them. As the verse enjoins, "Hear O Israel" — the Hebrew word for "hear," shema, also means "comprehend."

2) Heart: Study and contemplation give birth to emotion. Hence, "Hear O Israel" brings us to "and you shall love G‑d with all your heart, all your soul, and all your might" (ibid., verse 6).

3) Speech: When "these words are upon your heart" the next step is verbalization and communication — "And you shall teach them diligently to your children; and you shall speak of them when you sit in your house, and when you walk by the way; and when you lie down, and when you rise up" (ibid. verse 7). The last words in this verse are the source of the mitzvah to recite the Shema every evening ("when you lie down") and every morning ("when you rise up").

4) Body: "And you shall bind them for a sign upon your arm, and they shall be as tefillin between your eyes" (ibid. verse 8). Like a marriage ring one a finger, the tefillin are a physically tangible bond on our bodies embodying the our bond with G‑d and our commitment to make G‑d's oneness real in our world.

5) Environment: "And you shall inscribe them on the doorposts of your home, and on your gates" (ibid. verse 9). The last and ultimate phase is the mezuzah: a parchment scroll containing the verse of the Shema and affixed to the doorpost of the Jewish home — defining both the sanctity of environment within and its influence on the environment without.