What is the Sign of the Cross?
In the Christian religion, the sign of the cross is a hand motion many believers make that signifies the Trinity and reflects their profession of faith in God.
The hand motions vary slightly depending upon what Christian tradition is performing the action. The most common expression of the sign begins with the hand touching the forehead and then the lower chest or stomach area, which signifies the vertical beam of the cross. The hand then traces the horizontal beam of the cross across the shoulders.
Moving the hand from right to left is the tradition of the Eastern Orthodox Church. Moving the hand from left to right is the tradition of the Roman Catholic Church, the Anglican Church, and the Lutheran Church.
In most Eastern Christian traditions, the thumb, index finger, and middle finger touch forming a point, which represents the Trinity. The ring and pinky finger are pressed against the palm, which represents the human and divine natures of Jesus Christ. In Western Christianity an open hand is often used to make the sign, which in some traditions represents the five wounds of Christ.
The “Trinitarian formula” is spoken while the sign of the cross is made. When the forehead is touched, the speaker says, “in the name of the Father.” When the lower chest or stomach area is touch, the speaker says, “and of the Son.” When the horizontal beam is being traced across the shoulders, the speaker says, “and of the Holy Spirit.” Then the speaker says “amen.”The History
Some speculate that the idea for the sign of the cross originated in biblical passages that mention God marking a person.
For example, Genesis 4:15 reads, “Then the LORD said to him, ‘Not so! If anyone kills Cain, vengeance shall be taken on him sevenfold.’ And the LORD put a mark on Cain, lest any who found him should attack him.”
Also Ezekiel 9:4, which reads, “And the LORD said to him, ‘Pass through the city, through Jerusalem, and put a mark on the foreheads of the men who sigh and groan over all the abominations that are committed in it.’”
And Revelation 22:4 reads, “They will see his face, and his name will be on their foreheads.”
Evidence of the sign of the cross exists in early Christianity. For example, in the late second century, Tertullian wrote,
"In all our travels and movements, in all our coming in and going out, in putting on our shoes, at the bath, at the table, in lighting our candles, in lying down, in sitting down, whatever employment occupies us, we mark our foreheads with the sign of the cross." And in the fourth century, Chrysostom encouraged Christians to "never leave home without making the sign of the cross." After the fourth century, the sign of the cross was a common gesture in Christianity. It is referenced in writings of Christian authors and visualized in Christian art.
The Reformers In the 16th and 17th centuries, some Protestant Reformers rejected the sign of the cross as being a Catholic practice. This is perhaps, in part, why many Protestant traditions don't make the sign of the cross.
However, Lutheranism has utilized the sign of the cross in much of its liturgy (e.g. Luther’s Small Catechism). Martin Luther himself encouraged Christians to make the sign of the cross in many of his writings, including during their morning and evening prayers (“Prayers for Daily Use,” p. 26) and during spiritual warfare (Larger Catechism I:72-74). While less common in Methodism, using the sign of the cross is encouraged by the denomination.
And in some Presbyterian churches the sign of the cross is made on the forehead at baptism.