Exodus 15:26 New International Version (NIV)

26 He said, “If you listen carefully to the Lord your God and do what is right in his eyes, if you pay attention to his commands and keep all his decrees, I will not bring on you any of the diseases I brought on the Egyptians, for I am the Lord, who heals you.”

God promised that if the people obeyed him that they would not suffer from the diseases that plagued the Egyptians. Later these moral laws would keep them free of sickness. God’s laws are designed to keep us from harm. If you want God’s care, you need to submit to his directions for living.