Some diseases are a direct result of deliberate disobedience to God

2 Chronicles 21:12-15, 18-19

A letter came to him from Elijah the prophet, saying, “the LORD, the God of David your father, says, ‘Because you have not walked in the ways of Jehoshaphat your father, nor in the ways of Asa king of Judah, but have walked in the way of the kings of Israel, and have made Judah and the inhabitants of Jerusalem to play the prostitute like Ahab’s house did, and also have slain your brothers of your father’s house, who were better than yourself, behold, the LORD will strike your people with a great plague, including your children, your wives, and all your possessions; and you will have great sickness with a disease of your bowels, until your bowels fall out by reason of the sickness, day by day.’”