Isaiah 53:5 But he was wounded for our transgressions, he was bruised for our iniquities: the chastisement of our peace was upon him; and with his stripes we are healed
Sickness/infirmities and God’s sovereignty:
There are reason given in Scripture for sickness, disease and infirmities. In Jn 9:1-3 Jesus plainly declares that the man born blind was born blind for the glory of God in healing him after he had spent years in blindness. God chastens people with sickness, disease or infirmity (Num 12:10; 2 Chron 26:16-20; 2 Ki 5:27; 2 Chron 21:12-19). God also allows/brings infirmities and diseases upon us to humble us and bring us closer to Him (2 Cor 12:7-9; Gen 32:25). There is sickness, disease and infirmities upon the human race because of the fall of man’s original sin in the garden (Gen 2:16-17; Psa 90:10).
God seems to tell Moses that He made those that are blind, lame and so on (Ex 4:11). He takes credit for them, but did he purposely make them with infirmities or disease? We have to take into consideration the thoughts about why people are affected when we think about making them that way -- just as we see the fact that God created evil in Isa 45:7. Here it does not mean evil in the sense of sin, but it is the sorrow or evil that occurs when people disobey God and follow their own ways – the consequences of their ways (Gal 6:7).
God answers prayer:
We often struggle with the fact that we or others continue in sickness, disease or infirmities when we have prayed for them often or constantly. Is God required to answer our prayers? Do we contribute to the unanswered prayers? There are multiple factors involved in unanswered prayers and for us to blame God, our self or think we have improper theology because those prayers are not answered as we think or hope they would be answered is putting our finite person in a position of being god-like and taking upon us too much credit or insight.