The Shema is an affirmation of Judaism and a declaration of faith in one God. The obligation to recite the Shema is separate from the obligation to pray and a Jew is obligated to say Shema in the morning and at night (Deut. 6:7).
The first line of the Shema, "Hear O Israel, the Lord is our God, the Lord is One" (Shema Yisrael Adonai eloheinu Adonai ehad) (Deuteronomy 6:4) is repeated throughout the prayer services. It is said in the morning blessings, in the musaf Amidah of Shabbat and holidays, when the Torah is taken out of the Ark on Shabbat and holidays, as a bedtime prayer, as part of the deathbed confessional, and at various other times.
The commandment of saying Shema is fulfilled by reciting it in the shacharit and maariv services. The Shema should be said more audibly that the Amidah. Since the Shema reaffirms the basic tenets of Jewish faith, it is important to hear clearly what one is saying. The Shema may be said while standing or sitting. The Jews of Israel used to stand to show the Shema's importance and to demonstrate that saying Shema is an act of testifying in God (testimony in a Jewish court is always given while standing). In the ninth century, the Karaite sect used the practice of standing to claim that only the Shema passages of the Torah were of divine origin, so Jewish leaders stopped standing. Today, some Reform and Conservative congregations stand out of respect for the Shema. Orthodox congregations sit because the passages are from the Torah so it is as if a person is studying Torah when he or she recites them, and sitting is the position for study.
It is customary for worshipers wearing a tallit to hold the four fringes in the left hand while reciting the Shema. In the third paragraph of the Shema, when the word "tzitzit" is said three times and when the word "emet" is said at the end, it is customary to kiss the fringes as a sign of affection for the commandments.
When a person is praying alone, he begins the Shema with the phrase "God, Faithful King" (El melekh ne'eman) to bring the number of words in the Shema up to 248, the number of parts in the human body. This indicates that the worshiper dedicates his or her whole body to serving God. With a minyan, the chazzan repeats the end of the Shema so this phrase is unnecessary.
Jewish law requires a greater measure of concentration on the first verse of the Shema than on the rest of the prayer. People commonly close their eyes or cover them with the palm of their hand while reciting it to eliminate every distraction and help them concentrate on the meaning of the words. The final word, echad, should be prolonged and emphasized. Often, the last letter of the first and last words of the Shema verse are written in larger print in the siddur. This is because these letters form the word "ed," witness, and remind Jews of their duty to serve as witnesses to God's sovereignty by leading exemplary lives.
The next line of the Shema originated in the ancient Temple service. When the priests recited the first verse of the Shema during the service each morning, the people gathered in the Temple would respond "Blessed is the name of His Glorious Majesty forever and ever" (Barukh shem kvod malkhuto l'olam va-ed). This line became incorporated as the second line of the daily Shema. To indicate that it is not part of the Biblical passage of the Shema, it is said quietly, except for on Yom Kippur when it is recited out loud.
The three paragraphs of the Shema, comprised of biblical verses, were also said in the daily Temple service. The first paragraph is the continuation of the Shema verse, from Deuteronomy 6:5-9, starting with the word "v'ahavta." This paragraph deals with the acceptance of Divine rule. This section consists of an affirmation of belief in God's unity and in His sovereignty over the world, an unconditional love of God, and a commitment to the study of His teachings. It emphasizes the religious duties to love God, to teach Torah to one's children, to talk of Torah at every possible time, to put on tefillin, and to place mezuzot on the doorpost of one's home.
The second passage is from Deuteronomy 11:13-21, beginning with the word "v'haya." It declares the Jews' acceptance of the commandments and their undertaking to carry out the commandments as evidence of their loyalty to God. It talks of the fundamental principle in Jewish belief of reward and punishment that is based on the fulfillment of God's commandments.
It shall be, that if you obey My commandments that I command you this day to love the Lord your God and serve Him with all Your heart and with all your soul, then will I send the rain for your land in its season, the early [autumn] rain and the late [spring] rain, and you will gather in your grain, your wine, and your oil. And I will provide grass in your field for your cattle, and you shall eat and be sated. Be careful that your heart be not tempted and you turn away to serve other gods and bow to them. For then God will be furious with you and will block the heavens and there will be no rain and the land will not yield its produce, and you will perish quickly from the good land that God gives you. Take these My words to your hearts and to your souls, and bind them for a sign on your hands and for frontlets between your eyes. Teach them to your children: to speak them when you sit in your house and when you walk on the road, when you lie down and when you rise up. Write them on the doorposts of your house and on your gates. So that your days and the days of your children may be prolonged upon the land, which God swore to give to your forefathers, as the days of the heavens [are prolonged] upon the earth.
The third paragraph is from Numbers 15:37-41, beginning with the word "vayomer." It deals with the commandment of wearing tzitzit, which remind the wearer of God's commandments. It mentions the exodus from Egypt, which Jews are obligated to refer to each day. The last word of the Shema, "emet" (truth) is actually part of the next blessing and is not part of the Biblical passage. It is said as part of the Shema so that one can declare, "Hashem, your God, is true" (Adonai eloheichem emet).
The Lord spoke to Moses, saying, "Speak to the children of Israel and tell them to make for themselves tzitzit ("fringes") on the corners of their garments throughout their generations, putting a thread of blue upon the corner tzitzit. They will be for you tzitzit, you will see them and be reminded of all the Lord's commandments, and do them, and not turn aside toward your hearts and your eyes and stray after them. So that you remember and do all My commandments and be holy to your God. I am the Lord your God who brought you out of the land of Egypt to be your God; I am the Lord your God. Truth.
In Reform prayer books, the second paragraph of the Shema is often omitted because the doctrine of retribution is different in the Reform movement. The third paragraph is also left out because Reform Jews do not accept the commandment regarding fringes. Reform prayer books do include the end of this third section, from Numbers 15:40.
Sources: Donin, Hayim. To Pray as a Jew: A Guide to the Prayer Book and the Synagogue Service. NY: Basic Books, 1991. Kolatch, Alfred J. The Jewish Book of Why/the Second Jewish Book of Why. NY: Jonathan David Publishers, 1989 Schermon, Rabbi Nosson, editor. The Complet Artscroll Siddur. New York: Mesorah Publications, Ltd, 1984. Cardin, Rabbi Nina Beth. The Tapestry of Jewish Time. NJ: Behrman House, 2000.