Summary: The Roman Emperor Constantine saw the sign of a Cross in the sky which had a decisive effect on both his military career and spiritual life.
On 29th October AD 312 the first Roman Emperor converted to the Christian faith, Constantine the Great, entered Rome. He was a worshipper of the sun god, Sol. On 28th October the forces he commanded were trying to conquer Rome. There was a great battle to take a bridge leading to the city. His army was greatly outnumbered but he claimed to have seen the sign of the cross in the heavens, hearing the message “In Hoc Signo Vinces” (“In this sign you will overcome”). He claimed that God instructed St. Constantine to put the cross on all the shields of his men.
In fact it was the letters Chi-Rho, a symbol is composed of the first letters in the Greek word for Christ, which made the symbol of a cross. Constantine’s army won a decisive battle and from that day there was freedom in the Roman empire for Christians to worship Jesus. He didn’t become a Christian on the spot but the victory made a profound impression on him and before he died some 25 years later he was baptised as a Christian. And the next emperor, Theodosius, made Christianity the official religion of the Empire in AD380.
The sign of the Cross of Jesus is a powerful symbol of the Christian faith. The Apostle Paul wrote that he could not boast about anything other than the Cross of Christ, “May I never boast except in the cross of our Lord Jesus Christ” (Gal 6:14). Why did he say this because for Jesus it meant His death? To the Jews it was "a stumbling block". It was a symbol of weakness, humiliation and defeat. The Greeks also had a problem with the Cross. It offended their sense of reason. No sane person would believe that kind of tale. A cartoon has been found on a wall in the ruins of ancient Rome showing how crazy the Christian message seemed to the people of that time. It’s a caricature of Jesus’ crucifixion, showing a man’s body hanging on a cross - but the body has the head of a donkey. There’s also a figure of a young man with hand raised as if in worship. Underneath is the inscription, "He worships his God!"
A crucified god? It just defied all reason – it doesn’t make sense. The non-Christian says that God would never involve himself in the world like that! Do we believe that? Well, that’s the choice we have to make. The Bible tells us that Jesus went willingly to be crucified to bear our sin because there was no other way that we could be forgiven. It was on the Cross that Jesus paid the penalty for our sin. To those who will not believe on the Christ of the Cross, it’s inescapably offensive, but to those who believe, it’s powerfully effective as "the power of God unto salvation" (Rom 1:16).
The symbol of the Cross is the centre of our faith. It’s often embroidered on the pulpit fall or the communion table. Let it be a reminder to you of what Jesus did for you on the Cross to make possible your salvation if you’re willing to put your trust in Him and come to Him in repentance and faith.