Summary: A user-friendly explanation of the important biblical truths that the Sign of the Cross symbolises.
WHY WE MAKE THE SIGN OF THE CROSS
At many points in our worship we make the sign of the cross. Joining together 2 fingers and thumb we touch first our forehead, then move down to the bottom of the chest, back up and over to the left shoulder, across to the right shoulder.
It’s something that keeps cropping up in Christian Worship. Anglicans and Roman Catholics do it left shoulder to right shoulder; Greek Orthodox do it right shoulder to left; at baptism we make a little cross on the forehead of the baby; at the gospel we make a little cross on our forehead, lips and heart, asking that God may be in thoughts, our words and our heart as we receive his Gospel. So why do Christians keep making the Sign of the Cross?
The sign of the Cross is (quite obviously) a body prayer that Christians make and members of other religions do not make. We have much we can learn from the adherents of other religions: from their level of commitment to their beliefs; from their refusal to compartmentalise different parts of life as "religious" and "secular"; from the generosity, kindness and love that many of their members show. BUT all religions are different, and there are things we believe as Christians that are very different from what the adherents of other religions believe. In making the Sign of the Cross we are not just performing some ancient ritual for the sake of it. We are boldly asserting Christian truths about the way the world is.
IN MAKING THE SIGN OF THE CROSS WE ARE DIFFERENT FROM MUSLIMS
Muslims hold Jesus in high regard as a prophet - Isa al-Masih they call him. It is part of why they respect Christians as fellow "people of the book". But Muslims have a problem. They do not believe that someone as beloved to Allah as the prophet Jesus could have been degraded by the most humiliating and painful form of execution possible - death on a cross. Allah would not have allowed that to someone he loved so much. Therefore Muslims hold that at the last minute Jesus was miraculously swapped and someone else died in his place.
In making the Sign of the Cross we Christians assert that Jesus really did die on the Cross. That that death is not a failure but a victory - God’s plan by which we can receive eternal life.
Muslims hold that after death we are judged. If we have done enough good deeds to outweigh the evil deeds we have committed, then we will go to paradise. But if we have done more evil deeds we will go to hell. That is a scary thought. Every bad thing you have ever done takes you a step closer to hell. I know that if they are right, I am doomed. I certainly do not deserve to go to heaven. None of does. "All have sinned and fallen short of the Glory of God" (Romans 3:22).
But the wonderful news that the New Testament teaches us is that we don’t have to earn our way to get to heaven. Entry to heaven is a free gift from God that we don’t deserve, but that he gives us because he loves us. On the cross, God took the punishment that we deserve upon himself - so that we might be free to receive eternal life. All we have to do is say yes. In making the sign of the Cross we celebrate that wonderful, free, and undeserved, gift of everlasting life.
IN MAKING THE SIGN OF THE CROSS WE ARE DIFFERENT FROM JEWS
Obviously, in one sense we all are Jews. Before the fall of the Temple in AD70 there were many schools of Judaism: Zealots, Sadducees, Essenes, followers of John the Baptist, Pharisees, and followers of the Messiah Yeshua (Jesus). After the Roman armies crushed the rebellion of AD70, only two schools of Judaism survived - the rabbinic Judaism of the followers of the Pharisees; and the followers of the Messiah Yeshua - Christians. But while the New Testament describes us as "The New Israel", in every day parlance, we tend to talk about the heirs of the Pharisees as "Jews" and not use that term for ourselves.
Of course, we have much in common with our Jewish sisters and brothers - two thousand years of history, and large chunks of what we call "the Old Testament" (though in AD90 they cut out certain books that we kept on the grounds that they were "too Christian"). We both assert that we should "love [our] neighbours as [our]self" (Levit 19:18) and that we should "love the Lord God with all [our] heart and soul and mind" (Deut 6:5).
Nor should we ever fail to apologise for the atrocities that Christians have committed over the years towards our Jewish brothers and sisters - pogroms, genocides, knifepoint conversions, and (to some extent at least) complicity in the holocaust. Such atrocities have nothing to do with the message of Jesus, but we cannot deny that our people have committed them.