A benediction is a short invocation

Invocation

An invocation may take the form of:*Supplication or prayer.*A form of possession.*Command or conjuration.*Self-identification with certain spirits....

 for divine help, blessing

Blessing

A blessing, is the infusion of something with holiness, spiritual redemption, divine will, or one's hope or approval.- Etymology and Germanic paganism :...

 and guidance, usually at the end of worship service.

Judaism

Judaism

Judaism

Judaism ) is the "religion, philosophy, and way of life" of the Jewish people...

 developed ritualised benedictions (Berachot

Berakhah

In Judaism, a berakhah, bracha, brokhe is a blessing, usually recited at a specific moment during a ceremony or other activity. The function of a berakhah is to acknowledge God as the source of all blessing...

) for use at the Temple of Jerusalem, and the home. These Berachot often took the form of a blessing upon the fulfillment of a mitzvah

Mitzvah

The primary meaning of the Hebrew word refers to precepts and commandments as commanded by God...

(divine commandment). The most important benediction was the Priestly Blessing

Priestly Blessing

The Priestly Blessing, , also known in Hebrew as Nesiat Kapayim, , or Dukhanen , is a Jewish prayer recited by Kohanim during certain Jewish services...

 pronounced by the kohen

Kohen

A Kohen is the Hebrew word for priest. Jewish Kohens are traditionally believed and halachically required to be of direct patrilineal descent from the Biblical Aaron....

im (priests descended from Aaron

Aaron

In the Hebrew Bible and the Qur'an, Aaron : Ααρών ), who is often called "'Aaron the Priest"' and once Aaron the Levite , was the older brother of Moses, and a prophet of God. He represented the priestly functions of his tribe, becoming the first High Priest of the Israelites...

), as found in .

Christianity

From the earliest church, Christian

Christian

A Christian is a person who adheres to Christianity, an Abrahamic, monotheistic religion based on the life and teachings of Jesus of Nazareth as recorded in the Canonical gospels and the letters of the New Testament...

s adopted ceremonial benedictions into their liturgical worship, particularly at the end of a service. Such benedictions have been regularly practiced both in the Christian East

Eastern Christianity

Eastern Christianity comprises the Christian traditions and churches that developed in the Balkans, Eastern Europe, Asia Minor, the Middle East, Northeastern Africa, India and parts of the Far East over several centuries of religious antiquity. The term is generally used in Western Christianity to...

 and West

Western Christianity

Western Christianity is a term used to include the Latin Rite of the Catholic Church and groups historically derivative thereof, including the churches of the Anglican and Protestant traditions, which share common attributes that can be traced back to their medieval heritage...

. At the time of the Reformation

Protestant Reformation

The Protestant Reformation was a 16th-century split within Western Christianity initiated by Martin Luther, John Calvin and other early Protestants. The efforts of the self-described "reformers", who objected to the doctrines, rituals and ecclesiastical structure of the Roman Catholic Church, led...

, Protestants

Protestantism

Protestantism is one of the three major groupings within Christianity. It is a movement that began in Germany in the early 16th century as a reaction against medieval Roman Catholic doctrines and practices, especially in regards to salvation, justification, and ecclesiology.The doctrines of the...

 abandoned many of the benedictions of the Roman Catholic Church

Roman Catholic Church

The Catholic Church, also known as the Roman Catholic Church, is the world's largest Christian church, with over a billion members. Led by the Pope, it defines its mission as spreading the gospel of Jesus Christ, administering the sacraments and exercising charity...

, including the Apostolic Benediction made by the Pope

Pope

The Pope is the Bishop of Rome, a position that makes him the leader of the worldwide Catholic Church . In the Catholic Church, the Pope is regarded as the successor of Saint Peter, the Apostle...

 and his delegates, the "last blessing" of the dying, and virtually all benedictions of inanimate objects. However, the Anglican church retained the principle of benediction, and a benediction or blessing ends most Anglican services.

A common form of benediction in Baptist and liturgical Protestant churches is for the worship leader to raise his hands and recite the words of the biblical Priestly Blessing . This addition to the mass was made by Martin Luther in his Deutsche Messe and remains traditional in Lutheran Churches.

Some Protestant churches have recently started to reincorporate the use of benedictions in the closing of their church services. Such benedictions may be taken from Scripture, written by a church member, or a combination of the two.

An often complex and lengthy blessing before communion took place in the mass of the Gallican Rite

Gallican rite

The Gallican Rite is a historical sub-grouping of the Roman Catholic liturgy in western Europe; it is not a single rite but actually a family of rites within the Western Rite which comprised the majority use of most of Christianity in western Europe for the greater part of the 1st millennium AD...

 and in some French sees survived until the Gallican rites controversy when they were suppressed. Pope John Paul II, however, gave permission for these sees to restore this traditional element of their local rite.

In the Orthodox Church, benedictions will occur at both the beginning and the end of each service, and there may be other benedictions during the course of the service. The final benediction (the dismissal

Dismissal (liturgy)

The Dismissal is the final blessing said by a Christian priest or minister at the end of a religious service. In liturgical churches the dismissal will often take the form of ritualized words and gestures, such as raising the minister's hands over the congregation, or blessing with the sign of the...

) is the most important, and will often entail mention of the feast or saint

Saint

A saint is a holy person. In various religions, saints are people who are believed to have exceptional holiness.In Christian usage, "saint" refers to any believer who is "in Christ", and in whom Christ dwells, whether in heaven or in earth...

 being commemorated that day. The priest

Priest

A priest is a person authorized to perform the sacred rites of a religion, especially as a mediatory agent between humans and deities. They also have the authority or power to administer religious rites; in particular, rites of sacrifice to, and propitiation of, a deity or deities...

 will bless with his right hand, and the bishop

Bishop

A bishop is an ordained or consecrated member of the Christian clergy who is generally entrusted with a position of authority and oversight. Within the Catholic Church, Eastern Orthodox, Oriental Orthodox Churches, in the Assyrian Church of the East, in the Independent Catholic Churches, and in the...

 will bless with both hands. In both cases, the hand is held so that the fingers form the initials IC XC (the abbreviation for "Jesus Christ" in Greek), and he traces the Sign of the Cross

Sign of the cross

The Sign of the Cross , or crossing oneself, is a ritual hand motion made by members of many branches of Christianity, often accompanied by spoken or mental recitation of a trinitarian formula....

 in the air with his hand. If a bishop or abbot

Abbot

The word abbot, meaning father, is a title given to the head of a monastery in various traditions, including Christianity. The office may also be given as an honorary title to a clergyman who is not actually the head of a monastery...

 is holding his crozier while making the benediction, he will raise his right hand and trace the Sign of the Cross with both his crozier and right hand, crossing the one in front of the other. More solemn benedictions, such as that which comes at the end of the Divine Liturgy

Divine Liturgy

Divine Liturgy is the common term for the Eucharistic service of the Byzantine tradition of Christian liturgy. As such, it is used in the Eastern Orthodox and Eastern Catholic Churches. Armenian Christians, both of the Armenian Apostolic Church and of the Armenian Catholic Church, use the same term...

, will be made with a blessing cross

Blessing cross

A Blessing Cross is a hand cross held by a priest or bishop in Eastern Christianity when he gives a benediction. It is often made of precious metal and may be adorned with enamelwork, and precious or semi-precious gemstones...

 rather than the hand.

Benediction of the Blessed Sacrament

One of the most generally popular services in the Roman Catholic Church is Benediction of the Blessed Sacrament, commonly referred to as Benediction and known in France as Salut and in Germany as Segen. It is also the custom of some high-church Anglican churches to hold this service. It is ordinarily an afternoon or evening devotion and consists in the singing of certain hymns, or litanies, or canticles, before the Blessed Sacrament

Blessed Sacrament

The Blessed Sacrament, or the Body and Blood of Christ, is a devotional name used in the Roman Catholic Church, Eastern Catholic Churches, Old Catholic, Anglican, and Lutheran churches, to refer to the Host after it has been consecrated in the sacrament of the Eucharist...

, which is exposed upon the altar in a monstrance

Monstrance

A monstrance is the vessel used in the Roman Catholic, Old Catholic, and Anglican churches to display the consecrated Eucharistic host, during Eucharistic adoration or Benediction of the Blessed Sacrament. Created in the medieval period for the public display of relics, the monstrance today is...

 and is surrounded with candles. At the end, the priest, his shoulders enveloped in a humeral veil, takes the monstrance into his hands and with it makes the sign of the cross (hence the name Benediction) in silence over the kneeling congregation. Benediction is often employed as a conclusion to other services, e.g. Vespers

Vespers

Vespers is the evening prayer service in the Western Catholic, Eastern Catholic, and Eastern Orthodox, Anglican, and Lutheran liturgies of the canonical hours...

, Compline

Compline

Compline is the final church service of the day in the Christian tradition of canonical hours. The English word Compline is derived from the Latin completorium, as Compline is the completion of the working day. The word was first used in this sense about the beginning of the 6th century by St...

, the Stations of the Cross

Stations of the Cross

Stations of the Cross refers to the depiction of the final hours of Jesus, and the devotion commemorating the Passion. The tradition as chapel devotion began with St...

, etc., but it is also still more generally treated as a rite complete in itself. There is a good deal of diversity of usage in different countries with regard to details, but some of the elements are constant. The use of incense

Incense

Incense is composed of aromatic biotic materials, which release fragrant smoke when burned. The term "incense" refers to the substance itself, rather than to the odor that it produces. It is used in religious ceremonies, ritual purification, aromatherapy, meditation, for creating a mood, and for...

 and wax candles, which even in the poorest churches must not be less than ten in number , the singing of the "Tantum ergo

Tantum Ergo

Tantum ergo are the opening words of the last two verses of Pange Lingua, a Mediaeval Latin hymn written by St Thomas Aquinas. These last two verses are sung during veneration and Benediction of the Blessed Sacrament in the Roman Catholic Church and other churches that practice this devotion...

" with its versicle and prayer, and the blessing

Blessing (Roman Catholic Church)

Blessing in Roman Catholicism, in the narrow liturgical sense, is a rite consisting of a ceremony and prayers performed in the name and with the authority of the Church by a duly qualified minister by which persons or things are sanctified as dedicated to Divine service or by which certain marks of...

 given with the Blessed Sacrament are obligatory everywhere. In Rome the principle obtains that the only portion of the service which is to be regarded as strictly liturgical is the singing of the "Tantum ergo" and the giving of the Benediction which immediately follows. This idea is emphasized by the fact that in many Roman churches the celebrant, vested in cope and preceded by thurifier, acolytes, etc., only makes his entry into the sanctuary just before the "Tantum ergo" is begun. Previously to this the Blessed Sacrament is exposed, informally so to speak, by a priest in cotta

Surplice

A surplice is a liturgical vestment of the Western Christian Church...

 and stole; and then choir and congregation are left to sing litanies and canticles, or to say prayers and devotions as the occasion may demand.

In English-speaking countries the service generally begins with the entry of the priest and his assistants in procession and with the singing of the "O Salutaris Hostia

O Salutaris Hostia

O salutaris Hostia, "O Saving Host", is a section of one of the Eucharistic hymns written by St Thomas Aquinas for the Feast of Corpus Christi. He wrote it for the Hour of Lauds in the Divine Office. It is actually the last two stanzas of the hymn Verbum supernum prodiens, and is used for the...

" as soon as the Blessed Sacrament is taken out of the tabernacle

Church tabernacle

A tabernacle is the fixed, locked box in which, in some Christian churches, the Eucharist is "reserved" . A less obvious container, set into the wall, is called an aumbry....

. Indeed in England the singing of the "O Salutaris" is enjoined in the "Ritus servandus", the code of procedure approved by a former synod of the Province of Westminster. On the other hand, the Litany of Our Lady, though usually printed after the "O Salutaris" and very generally sung at Benediction, is nowhere of obligation. It may be added that further solemnity is often given to the service by the presence of deacon and subdeacon in dalmatics. When the bishop of the diocese officiates he uses mitre and crosier in the procession to the altar, and makes the sign of the cross over the people three times in giving the benediction. On the other hand, a very informal sort of service is permitted, where the means for carrying out a more elaborate rite are not available. The priest, wearing cotta and stole, simply opens the tabernacle door. Prayers and devotions are said or sung, and then the priest blesses those present with the veiled ciborium before the tabernacle door is again closed. The permission, general or special, of the bishop of the diocese is necessary for services where Benediction is given with the monstrance.
source: http://www.newadvent.org/cathen/02465b.htm