Commenting on the use of the sign of the cross in early Christianity and the Reformation (with particular emphasis on the Lutheran liturgy), Luther Reed wrote:
It is difficult to realize the hold which the sign of the cross has had upon popular imagination and life. Cyprian, Tertullian and many others are witnesses to its use among Christians as early as the end of the second century 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 occupieth us, we ark our forehead with the sign of the cross. For these and such-like rules, if thou requires a law in the Scriptures, thou shalt find none. Tradition will be pleaded to thee as originating them, custom as confirming them, and faith as observing them. That reason will support tradition, and custom and faith, thou wilt either thyself perceive, or learn from someone who hath perceived it. Meanwhile thou wilt believe that some reason there is, to which due submission is due” (Tertullian, Of the Crown).
Chrysostom concludes a glowing passage concerning the sign of the cross by saying: “When, therefore, thou signest thyself, think of the purpose of the cross, and quench anger and all other passions. Consider the price that hath been paid for thee, and then wilt thou be a slave to no man. Since not merely by the fingers ought one to engrave it, but before this by the purpose of the heart with much faith” (Chrysostom on St. Matt. Hom. Liv.).
As a reminder of the saving passion and death of Christ and an emblem of the mercy of God, the sign of the cross from the earliest times was accompanied by various formulas, such as “The sign of Christ,” “In the Name of the Father, and of the Son, and of the Holy Ghost.” Eventually the last came into universal use and supplanted all others. These words and the sign became a summary of the Christian faith, a simple yet comprehensive recognition of the Unity and the Trinity in the Godhead, and of the central significance of the sacrificial death of Christ.
The church at the time of the Reformation reacted against the excessive and superstitious use of the sign of the cross which had characterized the late Middle Ages. It did not abolish it, but endeavoured to restrict its use to significant occasions, such as baptism, the Lord’s Supper, the benediction at the end of the service, etc. Luther kept it, together with a form of the invocation, in his directions for morning and evening prayer in the Small Catechism. Thus he says: “In the morning when thou risest, thou shalt make the sign of the cross and say: May God, the Father, the Son, and the Holy Ghost, grant it”—a paraphrase which breathes the spirit of prayer even more definitely than does the original In Nomine, etc.
The church orders took for granted the use of the sign of the cross with the Invocation by the minister at the altar as part of his private devotion before the Service. When this became a public congregational act, the sign of the cross was gradually dropped. The formula which had accompanied it for so many centuries, however, remained as an invocation, that is, a solemn recognition of the Holy Trinity, and a petition for the divine presence and blessing. Thus the Lutheran Liturgy, at least in the German development, gave the Invocation a prominence and importance not found in the Roman Mass or in any other liturgy. (Luther D. Reed, The Lutheran Liturgy: A Study of the Common Liturgy of the Lutheran Church in America [rev ed.; Philadelphia: Fortress Press, 1960], 253-54)
