God created the world, in order that the greater multitude possible of creatures might experience the joy of existence — that joy, which He Himself experiences to the full.
God created everything good and nothing evil. The evil appeared because of the fact that some of the created by God spiritual creatures, angels and people, having the freedom of choice, chose the evil and rejected God and His good. God does not take away his long-standing gifts. Thus, having freely rejected God and the good, the devil throws all his forces at the seizure of other reasonable creatures, first angels, and then people, from God.
Why does God let it happen? We do not know. But we believe and profess, that at the end of ages everything will turn out to be good, due to the power of Divine love and wisdom.
This does not mean that we should not fight with the evil. On the contrary, the Lord unceasingly struggles with it and call us to do the same. The Lord wants us to love the good and hate the evil and to understand that any attack, directed at the Divine qualities, i.e. at love, mercy, truth and freedom, unavoidably causes attacking God — the struggle with God, which develops, because people turn away from God and incline towards the sin.
Let us, the believing Christians, pray to our Merciful God, so that He could reveal Hid holy truth to those receding Him and not searching for Him, in order they could perceive the truth.