Making the sign of the cross is catholic, but not simply in the Roman Catholic sense. It has been practiced by Christians almost since the time of our Lord’s resurrection from the dead. It has probably been around as a Christian practice as long as folding one’s hands to pray or saying before meal prayers. So in terms of its historic practice, Christians have been making the sign of the cross as long as there have been crosses.
The purpose and symbolism behind it is pretty simple and beautiful. When you are baptized, the pastor says these words over you “Receive the sign of the + holy cross both upon your forehead and upon your heart, to mark you as one redeemed by Christ the crucified” (Rite of Holy Baptism, Lutheran Service Book, p. 268). That was a part of the Baptism rite in Lutheran Worship (1982), as well as the “old” hymnal, The Lutheran Hymnal (1941). So the pastor literally makes the sign of the cross over the newly baptized, because in baptism we put on Christ, are buried with Him in His death, and we now bear His holy name.
When we make the sign of the cross, what we are doing is A) remembering our Baptism; B) Remembering Jesus’ death for our sins; C) Confessing to the world that I am not ashamed to be known as a disciple of Jesus; and D) Holding up the cross of Christ as the central core of my identity.
Martin Luther thought this practice so important that he included it in the Small Catechism. Making the sign of the cross is included as a part of both the morning and evening prayers.
So how do you make the sign of the cross? You put your thumb, index and middle finger on your right hand together (the Holy Trinity) and begin at your forehead. You then make a line with your hand from your forehead to the middle of your chest. You then raise your hand parallel with your sternum, and make the “cross” part from going from the left breast to the right.
Must the Christian make the sign of the cross? Certainly not. This is a matter of personal freedom and piety. Christians for centuries have found it beneficial to make a physical sign of the cross, but if that is not helpful do you, don’t do it and don’t feel bad about it. At the same time, I would ask that you not judge those who do make the sign of the cross. It is a matter of freedom, both ways.
God’s richest blessings to you in Christ, as we live under His cross.