Stories We Like: A Guide to the Comma
A ritual gesture common in the Roman Catholic Church, Eastern Orthodox Church, and Anglican Communion, made at the beginning and end of prayer as a reminder of Jesus' death on the cross. Worshipers make the sign by touching first the forehead, then the breast, and then each shoulder in turn, thus tracing in the air the shape of a cross.
a gesture of ancient Christian origin by which a person blesses himself, others, or objects. St. Cyprian explained the ritual in the 3rd century by reference to Christ's redemptive death on the cross. The sign of the cross is used throughout Christian liturgies, in moments of need or danger, at the beginning and end of prayer, and on numerous other occasions. In the Latin rite the sign is made in two ways: (1) the great sign, made with the five fingers outstretched (symbol of the five wounds of Christ) on the forehead, breast, and shoulders, left to right, and (2) the lesser sign, made with the thumb alone on the forehead, lips, and breast. In the Eastern churches, since the 7th century, the great sign is made with two fingers (index and middle, symbolic of the two natures in Christ as opposed to the Monophysite practice of using the index finger alone) or, since the 8th century, with the five fingers curved, index and middle fingers touching the thumb (a Trinitarian symbol). The Oriental gesture moves from right to left. The earliest invocation made with the sign seems to have been simply "The sign of the cross," or "The sign of Christ." Later a Trinitarian invocation was used-"In the name of the Father and of the Son and of the Holy Spirit." The Psalmist's invocation was "Our help is in the name of the Lord, who made heaven and earth."