Hallo
Why does God allow evil in this world and why is there evil.
Is this because this is a fallen world.
Is they Bibel versus that explain this
God Bless
Yes, there are Bible verses that explain why this present world is in such a fallen condition. But if you listen to men's organizational religious systems instead of God in His Word by The Holy Spirit, then you will never understand those Scriptures. In many ways, men's traditions counter that deeper understanding. Just the fact that you are wondering about it may be a sign from our Heavenly Father and His Son that you are supposed to know.
A Summary (but you'll have to study to find where this is written):
1. the devil sinned in the beginning. That happened in the old world, a world prior to Adam and Eve when Satan was actually perfect in following God, no sin, no death, a perfect creation. Satan was a covering cherub created to guard God's throne. Satan coveted that throne, wanting to be God. Thus the very first sin was not by Adam and Eve, but by Satan.
2. God ended that old world of Satan's rebellion with the waters of a flood (not Noah's day, but even before Adam and Eve). God then created this present world in a state of bondage to corruption. He gave Satan the power of death. God then planned out this present world and to offer His Son as the Perfect Sacrifice for those who would believe on The Father and The Son. God pre-ordained His elect to carry The Gospel to the peoples. God also allowed Satan to work with his followers against His Plan of Salvation, to serve as a tempter upon the rebellious and those who won't listen to God.
3. For this present world condition, it is in bondage because of Satan's rebellion of old. Although God destroyed the old world when Satan rebelled, God said He would not make a full end, thus today's creation condition is in bondage to corruption, i.e., imperfection. For this present world, everything decays and eventually dies. There is no salvation by this present world, but only in the world to come when Jesus returns.
4. The future world to come, particularly the new heavens and a new earth, will be about a type of return to God's original Perfect creation before Satan rebelled, but better. This is why the end of Revelation reveals that future world of no more death, no more sea, no feeling of hot or cold, no sin, no more hell, no more Satan and the wicked, and God's place on earth being established forever with His faithful.
5. God showed that He is 'using' Satan as a whipping rod upon the wicked and rebellious who deny Him. Satan has no power of his own, only what God allows him in order to deceive and tempt people's faith and beliefs. When Lord Jesus returns, Satan will be locked in his pit prison for the first 1,000 years of Christ's future reign, and then loosed one final time to go tempt the unsaved nations on earth, once The Gospel and The Christ has been revealed to all beyond any doubt to them. It will be a final pruning of those who refuse The Father and His Son.