How do Christian theologians explain the evil in the world?

The question of the evil in the world is one of the hardest ones in theology. The main argument for many atheists or sceptics is that, if there were God, and if he was good God, he whouldn’t allow the innocents to suffer so much. There is so much pain and misery in the world - how can we believe in God? The main answer that christian theologians offer is that the evil in the world is due to man's free will, given by God. God gave human beings free will - will to decide, whether to love him and follow his rules, or to disobey. He knew that some of his creatures will reject him, disobay his orders and do evil to other human beings, but he had to create even them and give them freedom, so the love between man and God would be possiblle. If there is no freedom, there is no true love, which was God's goal. If he decided to create just the creatures who are incapable to reject him, and capable just to love him, without making decision on their own, that wouldn't be true love. The main condition for love is freedom, and freedom of people caused evil in the world.