Sickness exists in the world only because of sin. There would be no sickness at all, neither mental nor physical, if man had not sinned. According to Christ sickness is bondage to the devil. (Matthew 8:16, 12:22; Luke 4:40-41, 13:10-17) And Christ has come to “destroy… the devil.” (Hebrews 2:14) With Jesus the forgiveness of sins, the healing of the body, the destruction of the devil and the raising of the dead are all one and the same act of salvation.
For which is easier to say, “Your sins are forgiven,” or to say “Rise and walk”? But that you may know that the Son of Man has authority on earth to forgive sins - He then said to the paralytic - “Rise, take up your bed and go home.” And he rose and went home. (Matthew 9:4-7, Mark 2:9-12, Luke 5:23-25)
In that hour He cured many of diseases and plagues and evil spirits, and on many that were blind he bestowed sight. (Luke 7:21)
Doing these things Jesus showed that He is Christ the Messiah, the fulfillment of the prophets who brings the Kingdom of God to the world.
...the blind receive their sight, the lame walk, lepers are cleansed, and the deaf hear, the dead are raised up, the poor have the good news of the gospel preached to them. And blessed is he who is not scandalized at me. (Luke 7:22-23; cf. Isaiah 29:1 8- 19, 35:5-6, 61:1; Matthew 4:23-24, 11:4-6)
When one is delivered from sin and evil, one is also freed from sickness and death. In the Kingdom of God there will be “no sickness or sorrow or sighing, but life everlasting.” (Requiem Kontakion of the Church)
When one is visited by sickness in this world, whether bodily or mental, he is a victim of the devil and the “sin of the world.” (John 1:29) This does not mean that people are necessarily being personally punished with their diseases. It means rather, as in the case of those born with infirmities and children who are ill, that where sin abounds, sickness and disease are also rampant. It is the teaching of the Church that those who are innocently victimized by sickness, such as small children and retarded people, are certain to be saved in the Kingdom of God.
This is the teaching of the book of Genesis. God did not say to man, “Sin and I will kill you.” He said, if and when you sin, “you will die.” (Genesis 2:17, 3:3) Thus when man sins and ruins himself by evil, he brings the curse of sickness and suffering to the world for himself and his children; and his life becomes toil until he returns to the dust out of which he is made - and which he is by nature without the grace of God in his life. (cf. Genesis 3:17-19) It is in this sense that the “prince of this world” is the devil. (John 12:31, 14:30, 16:11)
Given the sinfulness of the world, its bondage to the devil, its “groaning in travail” (cf Romans 8:19-23) until its salvation in Christ, God Himself uses sickness and death for His own providential purposes as the means for man’s salvation. God is not the cause of sickness, suffering and death; but given their existence because of the devil’s deceit and man’s wickedness and sin, God employs them that man might be healed and saved in the forgiveness of sins. In this sense, and this sense only, can it be said that “God sends sickness to man.”
When a spiritual person is sick he recognizes that his illness is caused by sin, his own and the sins of the world. He does not blame God for it, for he knows that God has not caused it and does not wish it for His servants. He knows as well, through the providential plan of God and the salvation of Christ, that his sickness will be healed. He knows also that if God so wills, he can be healed of his sickness in this life in order to have more time to serve God and man on earth, and to accomplish what he must according to God’s plan. He also knows as well that the very sickness itself can be the means for serving God, and he accepts it in this way, offering it in faith and love for his own salvation and for the salvation of others.
There is no greater witness to the love of God and faith in Christ than sickness endured with faith and love. The one who bears his infirmities with virtue, with courage and patience, with faith and hope, with gladness and joy, is the greatest witness to divine salvation that can possibly be. Nothing can compare to such a person, for God’s praise in distress and affliction is the greatest possible offering that man can make of his life on earth.
Every saint who ever lived suffered bodily infirmities. And all of them, virtually without exception - even when healing others by their prayers - did not ask for or receive deliverance for themselves. This is the case most evidently of Jesus Himself, the suffering servant of God.
He was despised and rejected by men, a man of sorrows, and acquainted with grief; as one from whom men hide their faces…
Surely He has borne our grieves, and carried our sorrows; yet we esteemed Him stricken, smitten by God and afflicted. But He was wounded for our transgressions, He was bruised for our iniquities, upon Him was the chastisement that healed us, and with His wounds we are healed…the Lord has laid on Him the iniquity of us all.
And they made His grave with the wicked and with a rich man (i.e. Joseph of Arimathea, Matthew 27:57) in His death…when He makes Himself an offering for sin…(Isaiah 53, cf. Psalms 22, 38, 41)
Christ “poured out His soul to death” (Isaiah 53:12) when He was only in the third decade of His life. Many of the saints hardly lived longer, and virtually all suffered, as did St. Paul, from some “thorn in the flesh,” normally understood as some bodily affliction.
...a thorn was given me in the flesh, a messenger of Satan to harass me, to keep me from being too elated. Three times I besought the Lord about this, that it should leave me; but He said to me, “My grace is sufficient for you, for my power is made perfect in weakness,” that the power of Christ may rest upon me…for when I am weak, then I am strong. (2 Corinthians 12:7-10)
All spiritual persons follow the example of Christ and Saint Paul and all of the saints in their appreciation of sickness. They say to the Father, “Thy will be done,” and transform their weakness, by the grace of God, into the means of salvation for themselves and others.