Sign of the Cross
The Sign of the Cross is a ritual performed mainly within Roman Catholicism and Eastern Orthodoxy, as well as Eastern-Rite Catholicism, Anglicanism, and Lutheranism. For the members of the Faith, it symbolizes by manifestly marking directly on one's own body or in the air, the four points of the Cross on Calvary. It also represents loving God with all one's heart, soul, mind and strength. There are two particular arrangements one is most likely to observe. One is followed by many of the Eastern Churches, the other by the Western (Latin) Rite of Roman Catholicism and the Oriental Orthodox.
Typically, the right hand is used. The thumb, index, and middle finger are brought to a point. They are then placed on the forehead, then moved down to the sternum. Western Rite Catholics, Anglicans and the Oriental Orthodox will then move the hand to the left shoulder or to the area of the left pectoral muscle, and then to the right; the Eastern Orthodox and most Eastern Catholics will do the opposite (i.e. right, then left). As one moves through the Sign, one recites, at the forehead, "In the name of the Father"; at the sternum, "and of the Son"; and across the shoulders, "and of the Holy Spirit, Amen." There are variations that occur. For example, some may mark a very large cross, or a very small one. Some may say "and of the Holy Spirit" across the shoulders. After moving the hand from one shoulder to the other, it may return to the sternum. It may be accompanied instead at times with the words of the Jesus Prayer in some form, or simply "Lord have mercy".
The thumb, index and middle finger brought to a point symbolize the Trinity, three persons sharing a single essence. The remaining two fingers are kept pressed close together and to the palm, representing the human and divine natures united together in Jesus Christ.
In the western Roman Catholic Church the direction of making the sign of the cross, which had previously been from right shoulder to left shoulder, as is still the custom among the Eastern or Orthodox Churches, was changed in the thirteenth century when Pope Innocent III (1198-1216), following the Great Schism between the Western and Eastern Churches and the subsequent hostility between the respective heads (the Pope and the Patriarch mutually excommunicated each other) directed that the sign was to be made with three fingers from the forehead to the breast and from the left to the right shoulder.
In Russia until the reforms of Patriarch Nikon in the 17th century, it was customary to make the sign of the cross with two fingers (symbolizing the dual nature of Christ). The enforcement of the three-finger sign was one of the reasons for the schism of the Old Believers whose congregations continue to use the two-finger sign of the cross.
Use of the sign
In Eastern Orthodox prayers, the sign of the cross is usually made whenever all three persons of the Trinity are addressed, or alluded to. Before commencing any prayer, in fact, the Sign is typically made. Upon entering a church, and the sanctuary within the church, one will make the Sign partly as an outward sign of reverence and veneration. Eastern Orthodox and Eastern Catholics will make the Sign as one way of venerating an icon; Priests have many more specific occasions upon which to make the Sign. Many members of the Faith will make the Sign in a way that may seem idiomatic to some: for example, if a member is exposed to blasphemy, he or she may make the Sign, partly to suggest subtly and politely to the speaker that an offense has been committed. Some members of the Faith will use the Sign in what almost appears to be a wish for luck; it may be that, or a part of an unsaid prayer for God's blessing, as when starting a travel, a sport competition or a bullfight.
The Sign of the Cross is made in other ways as well: it can be made in the air to bless objects, and it may trace a very small trajectory, such as on the forehead. For a member of the Faith, perhaps the essential element of the Sign is that it physically indicates the direct relevance of the Cross, of the Sacrifice of Jesus, to one's person or surroundings. It is an engagement of the body that affirms what the faithful professes. It is also a sign to others of what one professes.