Sickness is not from God. How do we know? One way is because, as mentioned earlier, after He created everything, "God saw all that he had made, and it was very good" (Genesis 1:31).
Because God has given man a free will, He is sometimes forced to allow sickness for certain purposes, but He does not cause it nor like it.
Sickness is from the devil, about whom Jesus said, "The thief comes only to steal and kill and destroy; I have come that they may have life, and have it to the full" (John 10:10).
We live in a world that has rebelled against God. It is a sin-sick world. Beginning with Adam, the first man, all people have broken God's laws. "All have sinned," the Bible says (Romans 3:23). Physical sickness is a result of the general condition of sin in the human race, and not always our own personal sin, although it may be, such as the many diseases transmitted through sexual promiscuity and other unhealthy behavior.
Deuteronomy chapter 28 tells us that sickness is a "curse" that man has brought upon himself for disobeying God and breaking His Commandments. Because of rebellion, the human race is under a general curse. The curse of sin brings not only eternal separation from God, but sickness.
God in His infinite mercy and kindness determined a way for that curse to be removed! He is the Judge of the universe. As a righteous Judge, He operates on 100 percent, totally consistent principles of justice. He is a holy and perfect Judge. Justice must always be served. Without exception, God must always punish sin, which can produce sickness. Otherwise, He would deny His very nature.
At the same time, He is a God of perfect love. God, then, was faced with the necessity of both judging and punishing sin, but also being perfect love.
Did God have a dilemma? Seemingly, but in His infinite, perfect wisdom, He had the perfect solution. He would take all our punishment upon Himself! That is what Jesus did, the glory of the gospel. He became our substitute, taking our sins and giving us His righteousness!
Jesus Christ, the Son of God, came from heaven to take all the judgment that we deserved.
God made him who had no sin to be sin for us, so that in him we might become the righteousness of God (2 Corinthians 5:21).
Christ redeemed us from the curse of the law by becoming a curse for us, for it is written: "Cursed is everyone who is hung on a tree (Galatians 3:13).
This was to fulfill what was spoken through the prophet Isaiah: "He took up our infirmities and carried our diseases (Matthew 8:17).
When we acknowledge what God has done for us and receive Jesus Christ as our Lord and Savior, we are no longer under a curse! By faith in Christ and His finished work on the cross, we can then receive all that God has provided for us.