Prayer is both an ritual obligation, and a personal spiritual experience. It's content is concrete and defined, in large measure, yet it is incomplete if it does not come from the heart. A full prayer service may only be conducted in the presence of a minyan (a quorum of 10) but private prayer is an essential part of even a communal service. The synagogue is a House of Prayer, but the home is also a place for prayer, as well.
Prayer is a mitzvah; that is, it is a commandment to pray three time each day. When the Temple in Jerusalem stood (the Second Temple was destroyed in 70 C.E.) sacrifices were made daily by the priests. In this manner, Jews served God. After the Temple was destroyed, the Rabbis instituted prayer services, which already existed in some rudimentary form, as a replacement for the sacrifices, a surrogate method of serving God.
The morning service is called Shacharit, the afternoon service is called Minchah, and the evening service is called Ma'ariv. On Shabbat and festivals, an additional service called Musaf is added to the morning service. The morning and evening services follow the same order which is characterized by:
The afternoon service is greatly abbreviated.
There is also a tradition that one should recite 100 blessings each day; most every event in one's day can inspire a blessing of appreciation.
Jewish prayers are, generally speaking, of three varieties:
Each type of prayer attunes one to a different aspect of one's relationship with God. Each type also attunes one to different aspects of oneself.
In Jewish prayer there is always a tension between prayer that is kavuah (fixed prayer, predetermined and set down in a prayerbook) and kavannah (prayer that is spontaneous and sincere). The development of the prayer service reflects this tension. Initially, the themes of the prayers and their order was laid down by the Rabbis. In time, they recognized that it is not always easy to pray, and it is difficult indeed to compose one's own prayers three times a day. So the Rabbis wrote prayers and people learned them. However, the Rabbis taught that one's prayer is not complete until one has added one's own thoughts, ideas, and feelings to the prescribed text of the prayers. Ideally, the printed prayers of the siddur (prayerbook) should be a springboard for our own prayers, giving them shape and inspiration, but filled in by the color and tone of our own prayers.
Jewish prayer involves all the physical senses in an effort to draw the worshiper in, body and soul. There are garment which are worn specifically for prayer and there is s a complex choreography to Jewish prayer. For morning prayers, a tallit (prayer shawl) is worn to enable the worshiper to fulfill the mitzvah (commandment) of wearing the tzitzit (ritual fringes). On weekdays, tefilin is also worn by many worshipers. Tefilin are small lacquered boxes containing parchment scrolls on which are inscribed passages from the Torah. The tefilin are worn in fulfillment of the commandment, "And these words which I command you this day... you shall bind them for a sign upon your hand and they shall be for fronlets before your eyes. (Deuteronomy, chapter 6). A kippah (head covering) is worn to remind the worshiper that there is something above us, and as a sign of respect for God. Jewish prayer involves movement. There are prayers said standing, other may be recited while seated. Often worshipers will sway to the rhythm of their own prayers. There are times when the worshiper kisses the tzitzit, times when he or she rises up on his toes in imitation of the angels in heaven, and times when he or she stands perfectly still. Jewish prayer involves music in many forms. Most of the service is chanted. There are many prayers which are sung to congregational tunes. The Scriptures (both Torah and Haftarah) are chanted to special tunes reserved for these sacred texts). There are musical themes associated with each of the holy days, and many of the prayers are chanted to these tunes (called nusach).
I am frequently asked about the relative merits of collective worship and private worship in Jewish tradition. Certainly people can pray by themselves, but collective worship is also essential at regular intervals because it brings the community together *as a community* and that is important. Judaism is not a religion of the individual. It is more than a faith. It is a family-centered and community-based culture and civilization. It fosters interdependence and relationships with others.
Here is but one example: When someone has died, the mourners are obligated to recite a prayer called Kaddish each day for a stipulated period of time. In order to recite the prayer, they need a minyan (the quorum required for public prayer). The result is that the community assembles in their home while they are in mourning to enable the mourners to say Kaddish and thereby are able to provide support and consolation. Once the period of mourning is completed (seven days), then the mourners need to come to the synagogue to join the minyan there to say Kaddish. The result again is that they cannot isolated themselves in their grief, but must come back to the world and back to the community, where they will be supported and nurtured as they work through their grief.
Are there times when one may pray alone? Yes, certainly, but that cannot function as the mainstay in the life of a Jew. Jews need to come together to accomplish the many-faceted aspects of worship: prayer, study, celebration. All these things require the presence of other people; all are enhanced by the presence of other people. Hence collective worship is very important -- indeed essential -- for Jews.