If God made everything why did he make bad things? For example: diseases.
Most misunderstandings concerning God stem from our natural assumptions. Since God is "the Creator" people naturally assume that everything that exists today was created by God. This is false.
It is true that the Bible explicitly says that "God created all things" (Ephesians 3:9; Revelation 4:11), but these references point to the six days of Creation as recorded in the book of Genesis chapters one and two. After each of those days of Creation we are told that God looked at all He had made and pronounced it to be "good." That obviously leaves us with the profound issue of explaining the existence of all the "bad" things we see in our world every day. (The origin of evil has been a favorite subject of philosophers throughout the centuries.)
The Bible explains the origin of all that you and I consider bad and evil in the 3rd chapter of Genesis, and it all begins with the introduction of sin into the world. The Bible tells us that with sin came death. That means, physical death was not a part of God's original Creation. He never intended man to suffer the ravages of old age, sickness, disease and all the accompanying ills that go with it. Technically speaking, man created those things by his choice to fall into sin.
The Apostle Paul wrote to the Christians in Rome in the New Testament saying: "just as sin entered the world through one man, and death through sin, and in this way death came to all men" (Romans 5:12 NIV) This passage agrees with the narrative of Genesis, reminding us that sin came into the world...and death was the result.
It's important to ask these kinds of questions for two reasons:
First, without a proper understanding of the origin of sin and death, we see a twisted and perverted image of the character and purpose of God. Instead of a loving and caring Creator, we see Him as One who inflicts the worst conditions upon His unsuspecting creation, filling their lives with pain, darkness and hopelessness. (That certainly isn't a God I would want to worship!)
Secondly, when we understand that everything we see around us as "bad" is a result of sin, we are now ready to recognize the reason God sent His Son to this earth. Jesus came for the expressed purpose of overturning the dominion of sin and death. This He did by bearing the penalty of sin, and conquering it by rising from the dead. I would encourage you to read our information about Christ's work on the cross on our page about Connecting with God.