We do not have a logical reason for the existence of evil in a universe created by a God of love. Both human wickedness and natural disaster power enormous problems for Christians. There is a temptation to blame all such evil on Satan.
The Bible offers no explanation of the problem of evil, but teaches that God is in control. Ultimately, even opposing powers conform to his plans, although against their will.
Evil that arises from the wickedness of human beings can be seen as a risk of our creation as free, personal beings, made in the image of God. We were made to respond freely to the love of God, a freedom that must include the freedom to refuse. God’s plan to save us from the consequences of rejecting him led to the death of Jesus on the cross.