"Why does a Good God allow evil in the world?"

This is a question I imagine everyone has asked at one point in time.

And it is an area those that believe in God have struggled or may still be struggling with.

Especially since God has been touted as the all-knowing, all-seeing, all-powerful, etc. 

Why will such a good Person stand back and watch so much evil unfold in the world He created?

To get perspective on this, we have to go back to the very beginning.

In the beginning, God creates a good and perfect world. It is so good, that He Himself notes this seven times in the biblical account in Genesis.

God hands over the dominion of this perfect world to man. He gives him rulership of the sea, the sky, and everything on the ground (Genesis 1:28).

And in our world, we can see humanity's dominion in effect. We have indeed through science and technology conquered the earth, and are boldly exploring the regions beyond. Everywhere you go, you see our domination of the planet through technology, civilization, and culture.

Unfortunately, man sins and falls. And his dominion is corrupted through this. Every aspect of man's domination of this earth has been tainted by this fall.

If we critically look for the source of all the types of evil in this world, we find sin at the root. Devastating wars come because of the greed in humans that makes them covet what belongs to others - oil, gold, and other natural resources. Cancers and other debilitating diseases come by because humans are being exposed to harmful chemicals, again through the greed of those that selfishly choose gain over the wellbeing of others. And on and on, everywhere we trace the thread of suffering in this world, we find that the root is sin.

But what about the good God from the beginning? Why is He just standing back, watching this all unfold? Why doesn’t He do something?

He has intervened once. The Bible records how sickened He was at the level of evil in the heart of man that He does a reset by flooding the entire earth. To clean the slate and start things over. And He preserved those who could be trusted to continue a good lineage. But the challenge is that the problem is in the heart of man. A few generations after, the evil was back.

This is how the Bible puts it "The heart is deceitful above all things, and desperately wicked: who can know it?" - Jeremiah 17:9

We have to ask again: why does God stand back, still! Why doesn't He just reach back and take things over? He gave the dominion to man, why doesn't He just reach and take it back? Since man is making such a mess of things.

But we have to remind ourselves of a key attribute of God - consistency. God takes pride in the stability in His word. The Bible says God magnifies His word over His name (Psalm 138:2). His word is His bond. If He says a thing - it is established forever and does not change.

This stability of God's word is what even makes this earth a sustainable place to live in. God declared sunrises and sunsets in Genesis 1, and we will have sunrises and sunsets till the end of time, whether He is angry, or He is happy. We can confidently tell our friends "See you next week Monday!" without thinking twice, because we have come to know through the stability in the motion of the sun and earth that we will have sunrises and sunsets till our next meeting. 

This stability is also demonstrated in natural phenomena: the many laws of science like gravity, motion, and momentum that we can trust to work when we expect them to are linked to this attribute of God. We can launch a rocket to the moon and trust that the stability in the laws of science will guarantee it reaches there. We can get into a car, turn on an engine, and trust that the laws of force, combustion, gravity will come together and make it work as expected.

Jesus alludes to this in Matthew 5 when He calls God the Father that "makes the sun to shine on both the evil and the righteous". That's the stability and consistency in God. God has given His word, that man will dominate the earth. And that word will stand to the very end. 

But as a good God, the evil that we are subjected to in this world grieves Him deeply. He loves us and He hasn't given up on the world. And this is why He came up with the salvation plan, through His Son, Jesus. 

"For God so loved the world, that He gave His only Begotten Son, that whosoever believes in Him will not perish, but have everlasting life" (John 3:16)

This salvation plan has several things rolled up in it. It includes a way to transform the heart of evil in humans to a heart of good, a plan to save humans from the wages of sin - death. At its heart is a plan to re-establish the reign of godliness on this earth, by infiltrating the ranks. The same humans who have been given dominion of the earth and have used that power to perpetuate evil will be transformed through salvation in Christ to use that same power to perpetuate good in the world. 

This is why evangelism and conversion are the cornerstones of Christianity. This is why the Bible allots a significant portion to instructions on how to treat each other with love and live godly lives because that is the key to conquer the evil we see in the world - to shine the light so bright that darkness has no place.

But God knows that He has to bring a definite end to evil in this world - there is only so much that pockets of Christians can accomplish in their own personal campaigns of love and godliness. This plan has been laid out and is recorded in the book of Revelation - the last book of the Bible.

So no, God is not standing idly by, allowing evil in the world. He is hard at work, through His Son, His Spirit, and His children on earth, to bring an end to evil and restore the reign of good on this earth.

TL:DR 

God created a good world and handed it over to humans. 

Humans polluted this good world with evil through sin. 

God's word is His bond so He's not taking back dominion. 

But He has been working tirelessly over the ages to bring the world to restore good to this world.

And this is the plan of salvation through His Son Jesus Christ.