We call ourselves Christians because we believe in God as we were taught to believe by the Son of God Himself, our Lord Jesus Christ.
Jesus Christ not only taught us to believe in God correctly, but He also saved us from the power of sin and eternal death.
The Son of God, Jesus Christ, out of love for us sinners came down from Heaven and, as a man, suffered instead of us for our sins: He was crucified, He died on the Cross, and on the third day He resurrected. As the sinless Son of God, by His Cross (that is, by suffering and death on the Cross for the sins of all men and of all the world), He conquered not only sin but also death itself—He arose from the dead, and He made the Cross the weapon of His victory over sin and death.
As the the vanquisher of death, Who arose on the third day, He saved us also from eternal death. He will resurrect all of us, all the dead, when the last day of the world comes; He will resurrect us for joyful, eternal life with God.
The Cross is the weapon―or sign―of Christ’s victory over sin and death. Our Lord Jesus Christ received in His breast the terrible spears of sin and death which were invincible for us. He died on the Cross, but He also arose, as the vanquisher of sin and death, and thus opened for us the way to eternal life.
Now everything depends on us: if we wish to be delivered from the power of evil, sin, and eternal death, then we must follow Christ, love Him, and fulfill His holy will, being obedient to Him in everything, and live with Christ.
This is why, in order to express our faith in Jesus Christ our Savior, we wear a cross on our body, and during prayer we form the cross over our ourselves with our right hand—that is, we make the sign of the Cross.
For the sign of the Cross we put the fingers of our right hand together as follows. We bring the tips of the first three fingers together (the thumb, index, and middle ones), and bend the last two (the “ring” and little fingers) against the palm.
The first three fingers express our faith in God the Father, God the Son, and God the Holy Spirit, as the Trinity one in essence and indivisible. The two fingers bent signify how the Son of God, when He come down from Heaven, being God, became man: that is, they signify His two natures—divine and human.
In order to make the sign of the Cross, with our fingers in this position, we touch our forehead, for the blessing of our mind, our stomach, for the blessing of our internal feelings, then our right and left shoulders, for the blessing of our bodily strength.
The sign of the Cross gives us great strength to repel and conquer evil and to do good, but we must remember to make the sign of the Cross correctly and without haste, otherwise it will not be the sign of the Cross, but just waving our our hand around, which only gladdens the demons. By making the sign of the Cross carelessly we show a lack of reverence for God. This is a sin, called sacrilege.
When we cross ourselves, mentally we say, “In the name of the Father, and of the Son, and of the Holy Spirit. Amen.” Thus we express our faith in the All-holy Trinity and our desire to live and labor for the glory of God. The word Amen means: in truth, truly, let it be so, so be it.