To make the sign of the cross, Orthodox Christians lift the right hand and touch the forehead, the lower chest or abdomen, the right shoulder, and the left shoulder. That movement from shoulder to shoulder is the opposite of the custom in the West, where the hand goes from left to right.
When Orthodox Christians make the sign of the cross, they position the thumb and first two fingers of the right hand together at the tip, to represent the Trinity. This is what you use to touch forehead, abdomen, shoulder, and shoulder. The ring and little finger are held together, to represent the two natures of Christ; they are bent down to touch the palm, to represent his descent to earth.
Some Christians mistrust the sign of the cross, thinking of it as a relic of medieval superstition. It’s a gesture that goes back much earlier, though, even to the years of Roman persecution. Tertullian (AD 160-225) cautions Christian women not to marry unbelievers: “Will you escape notice when you sign your bed, your ‘dear little body’?” He warns that the husband who sees this and realizes his wife is a Christian might use it against her, threatening her with arrest and execution. This was still the age of martyrs.
It’s interesting that Tertullian doesn’t then say, “So stop making the sign of the cross.” To refuse to bear the cross of Christ, to conceal it even for personal safety, was simply not possible. “Far be it from me to glory except in the cross of our Lord Jesus Christ” (Gal.6:14).
To the early Christians the sign of the cross was not a merely symbolic gesture, but a way to invoke the immediate presence and power of Jesus Christ.
St. Athanasius (about AD 320) invited skeptics to test this for themselves: “Let him who would test this by experience, in the presence of lying demons and fraudulent oracles and magic, let him use this sign of the cross which they laugh at. He will see how it makes demons take flight, oracles cease, and all magic and witchcraft is ended.
Trusting in such power, the early Christians made the sign of the cross frequently. “Let the Cross, as our seal, be boldly made with our fingers upon our brow and on all occasions,” says St. Cyril of Jerusalem (AD 313-386), “over the bread we eat, over the cups we drink, in our comings and in our goings, before sleep, on lying down and rising up, when we are on the way and when we are still.
(Presvytera Frederica Mathewes-Green)