Certain religions and philosophies see evil and good as eternal forces that will always exist in the universe. Both are necessary for the right operation of the universe. Evil and good are opposites that require each other. If there were no evil, there could be no good. The yin and yang is a classic picture of this viewpoint.
A more modern version of this concept is the idea that evil is absence of good. Just like dark is the absence of light and cold is the absence of heat so evil is the absence of good. Since there is light dark must also exist. Since good exists, there must also be evil. But must it?
Evil is not necessary. God existed for eternity before creating the universe. God existed without evil. God continues to exist without evil. God will exist through all the eternity to come without evil. Evil is not necessary to God, but what about to men?
When God created the universe everything was perfect. Satan had not rebelled and man had not sinned. How long things lasted before sin is unknown. The universe functioned just fine without sin.
Evil is not just the absence of good. Evil is the rejection of God. Sin originated in Satan when he determined to rebel against the rule of God. Sin came into the world when man doubted the goodness of God and chose to reject God’s commands in favor of a promise to be like God. Evil is always the rejection of good and rebellion against God.
Evil is not necessary. Evil is sand in the gears of creation. Evil is a destructive influence that hinders the proper working of all things. Evil and all the consequences of sin- death, pain and sorrow- are not necessary. They will not last. The present age is marred by evil but this age is short.
A time is coming when all evil be removed from the universe. All of wicked humanity, all the rebel angels and Satan himself will be thrown into the Lake of Fire. The influence of evil upon the universe will be removed.
The universe that now exists is entirely corrupted by sin. “For we know that the whole creation groaneth and travaileth in pain together.” (Romans 8:22) God will destroy this universe. “the heavens shall pass away with a great noise, and the elements shall melt with fervent heat, the earth also and the works that are therein shall be burned up.” (2 Peter 3:10) God will create a new universe which will be as perfect as the original creation. Revelation 21 and 22 describe the coming universe as eternally unstained by sin.
Evil is not necessary. Evil exists for a brief time, but the eternal universe which is coming will be forever free of sin and all its consequences.