Many people wonder how a good God can allow evil to continue and flourish in this world. This is known as The Problem of Evil, and some folks use this problem as an excuse to deny the existence of God. But they don't realize that if God doesn't exist, then evil ceases to be a meaningful category. For evil to exist at all, there must be a good God to measure evil against.
The ancient Greek philosopher Epicurus famously asked: “Is God willing to prevent evil, but not able? Then He is not omnipotent. Is He able, but not willing? Then He is malevolent. Is He both able and willing? Then where does evil come from? Is He neither able nor willing? Then why call Him God?”
But this is a false dichotomy; there is actually a third option, revealed by Scripture: The almighty God who is perfectly good and also in control of all things has a temporary purpose for evil, but the Day is coming when He will sit in judgment to right absolutely every single wrong that has ever occurred. Without a Day of Judgment, the charge of malevolence in God might stand, but because there is coming such a Day, all of God's goodness, justice and wisdom is vindicated.
Sometimes people ask: Why does God allow bad things to happen to good people? Why do innocent people suffer? This is not so much questioning the goodness of God as it is questioning the fairness of God. But the Bible declares that there is no such thing as “good” or “innocent” people. It says that all have sinned and fall short of the glory of God. There is no one righteous, not even one; there is no one who does good, not even one. (Rom 3:23, 3:10-11) Therefore, no one deserves that God should treat them well or fairly; no one deserves a life free from suffering or pain. As rebel sinners against the holy God, we really deserve all manner of wrath poured out upon us. We should actually wonder why God doesn’t give us more suffering in this life as punishment for our sin against Him. God has every right to treat rebel creatures any way He wants. And yet, in His common grace, He causes His sun to shine upon the good and the bad, and causes His rain to fall upon the righteous and unrighteous (Matt 5:45).
God could have created a perfect world where He did not allow sin and evil to enter, where all things were very good all the time. In such a world, God’s goodness, compassion, mercy and love are on display, but not His justice and holiness and righteousness. On the other hand, God could have created a perfect world where He allowed sin and evil to completely ruin, corrupt and destroy under His wrath. Here God’s justice and holiness would be demonstrated, but not His goodness and merciful love. In order to put on full glorious display His full character, both His good love and His holy justice, He created a perfect world and allowed sin and evil to enter, so that He could show both His love and His justice in redeeming it.
God Himself knows suffering and pain and evil, for the second Person of the triune God, the Son, entered into His creation to join humanity to Himself and experience evil perpetrated against Him. He was rejected, slandered, mocked, spat upon, beaten, and nailed to a cross to suffer one of the most cruel, evil deaths imaginable. But in the cross, the good love of God and the holy justice of God come perfectly together. Only Christianity solves the problem of evil, because only Christianity has the cross of Calvary at its center.
The cross reveals the outpouring of God’s just wrath upon sin, for in 3 hours of darkness, Jesus the Son of God bore His Father’s wrath over sin upon Himself, even though He was innocent and perfectly sinless. He was bearing the wrath of God over the sin of His people, His sheep who would believe in Him. He was their substitute and sacrifice, taking upon Himself the punishment that they themselves deserved. The cross reveals the outpouring of God’s love for His people, because He offered His own most beloved Son up on the altar of the cross for them. In the cross, God’s goodness and justice come together in full display: His wrath over sin/evil together with His love for His people.
The cross is also a promise, that one Day coming soon, God will declare “Enough!” and the Lord Jesus Christ will sit down on the Great White Throne of Judgment, and He will bring final Judgment upon every evil and wicked deed that has ever been committed by the children of man. But that includes the evil in your own heart, your own personal sin and disobedience and rebellion against God. That too will be judged… and fully punished. Your punishment for your sin will fall entirely upon your own head, or it will have had fallen entirely upon Jesus' head on the cross for all those who have trusted in Him. Every person whose name is not written in the Lamb’s Book of Life will be thrown into the eternal Lake of Fire prepared for the devil and his angels. God’s justice will be fully glorified on that Day. If you want your name written in the Lamb’s Book of Life, you must repent of your sin and trust fully in Christ’s sacrifice on the cross, that it washes away all your sin before God, in full surrender of your life to Jesus Christ as your Lord. All who trust in Jesus will be saved from the eternal Wrath of God on the Day of Judgment. God’s goodness and love will also be fully glorified on that Day, as He declares His people in Christ acquitted and saved, ushering them into His eternal Kingdom.