Illnesses are the tests of this world

Illnesses are means by which believers can show their passion for and devotion to our Lord. People who believe in God and submit to the destiny created by Him show their contentment with all that comes from Him by not forgetting that all sickness and health comes from God. In this way, by God’s leave, they turn times of sickness into blessings of reward.
Illnesses are one of the things that serve to remind people of their weakness. The otherwise well-protected human body can still be severely affected by a virus or microbe too small to be seen with naked eye. At first sight, this weakening of the body might not be what one would expect. God has created the human body with immaculate defense mechanisms. Indeed, the human body’s defense system can be described as a “powerful army.” Yet people still frequently fall ill. Of course, if God, Who installed such superior systems inside the human body so wished, nobody would ever fall ill. Viruses, microbes and bacteria would have no effect on them, or else these specially created tiny “foes” would never have existed in the first place. Yet everyone can contract an illness with such minute causes that give rise to serious consequences.
These dangers are not far off and remote; they can easily befall anyone at any time. It is a grave error to assume they are natural events and never think about them. Like all other weaknesses, illness is specially created by God. Human beings, with their tendency to arrogance, can thus see how feeble they truly are. They can also grasp the deficiencies of this world.
Illnesses are tests bestowed on Muslims by God so that they can desire Paradise, give thanks for God’s mercy and the blessing of good health, and submit to Him in the knowledge of their own weakness. They always hope for health from God, knowing it is He Who bestows sickness and health. They remember God at every painful moment and keep their hearts bound to Him. The words of the Prophet Abraham (pbuh) on the subject are revealed as follows in the Qur’an;
“When I am ill it is He Who heals me.” (Surat ash-Shu’ara, 80)
What is the wisdom behind the creation of disease?
Sickness reminds people of their weakness and their need of God. Human beings incapable of preventing the harm a microscopic virus does to their bodies are thus better able to understand their weakness and how much they need God.
Sickness makes one appreciate the fact that good health is a great blessing from God. Someone who does not become ill for a long time, and therefore feels no pain or discomfort, becomes used to that state of affairs; but when he is confronted by sickness, he will immediately realize that good health is indeed a great blessing from God.
In severe illnesses, people may reflect more on the transitory nature of the world, and on death and the hereafter. Some people who contract a life-threatening disease or who lose the use of their limbs may regard this as an unwelcome development yet that disease may have been bestowed on them, not as a source of trouble, but as a means whereby they can attain salvation in the hereafter and turn to God alone: One prays more and draws closer to God in times of sickness. As the symptoms of a severe illness begin increasing in the body, one may begin reflecting on death, which one has perhaps never much thought of before, and thus wish to be restored to health by praying to God with all one’s heart.
Someone who never fully submitted to God before falling ill may acquire that virtue through sickness and may hope to attain the eternal blessings of Paradise in the face of brief discomfort in the life of this world.
If God so wished, nobody would ever fall ill or suffer pain but there is much wisdom behind the experiencing of such discomfort in terms of grasping the transitory nature of this world and the infinite might of God.
It must not be forgotten that it is most important to sincerely grasp this fact and to be able to behave with virtue in the face of such events.
In the face of illness, people reflect on how meaningless their devotion to this world is; they realize that the things they own are temporary and given to them in order to test them. Someone whose life is threatened by a single microbe inside his body and is quite unable to fight that microbe off will grasp his helplessness, and realize that it is God Who created him and protects him from dangers. No matter how great someone may imagine himself to be, he is unable to do anything to benefit himself or to protect himself from harm unless God so wishes. If God so wishes, He will send sickness, and if He so wishes, He creates weaknesses in the human body to remind people of their helplessness.
As said earlier, this world is a place of testing created by God. Everyone has a responsibility to perform good deeds that will please Him and is tested accordingly. At the end of the test, those who abide by God’s commandments and prohibitions will earn the right to live in Paradise for all time, but those who insist on being arrogant and prefer the few decades of this world to the eternal life of the hereafter will be unable to escape the deficiencies, troubles and weaknesses in this world and in the hereafter.