Feast of the Exaltation of the Cross
INASMUCH, therefore, as the Cross has become as it were the altar of this fearful sacrifice—for on the Cross the Son of God died for the fall of man—therefore the Cross is justly revered and worshipped and depicted as the sign of the common resurrection of all men, so that those who bow down before the wood of the Cross might be delivered from the curse of Adam and receive the blessing and grace of God for the doing of every virtue. For Christians the Cross is magnification, glory, and power: for all our power is in the power of Christ Who was crucified; all our sinfulness is mortified by the death of Christ on the Cross; and all our exaltation and all our glory are in the humility of God, Who humbled Himself to such an extent that He was pleased to die even between evil-doers and thieves. For this very reason Christians who believe in Christ sign themselves with the sign of the Cross not simply, not just as it happens, not carelessly, but with all heedfulness, with fear and with trembling and with extreme reverence. For the image of the Cross shows the reconciliation and friendship into which man has entered with God.
Therefore the demons also fear the image of the Cross, and they do not endure to see the sign of the Cross depicted even in the air, but they flee from this immediately knowing that the Cross is the sign of the friendship of men with God, and that they, as apostates and enemies of God, being far from His Divine face, do not have any longer freedom to draw near to those who have become reconciled with God and united with Him, and they can no longer tempt them. And if it seems that they tempt certain Christians, let everyone know that they battle against those who have not properly understood the exalted mystery of the Cross.
But those who have understood this mystery and in very fact have known in experience the authority and power which the Cross has over demons, have likewise understood that the Cross gives the soul strength, power, meaning, and divine wisdom. These with great joy cry out: “Far be it from me to glory, save in the Cross of our Lord Jesus Christ, through which the world is crucified to me and I unto the world” (Gal. 6.14). And thus, inasmuch as the sign of the Cross is great and fearful every Christian has the duty to make it with fear and trembling, with reverence and heedfulness, and not simply, and not as it happens, simply out of habit and carelessly: for according to the degree of the reverence which one has towards the Cross, he receives corresponding power and help from God. To Him may there be glory and dominion forever. Amen.
—St Symeon the New Theologian, The First-Created Man