II Kings 8:12 KJB
God is patient and longsuffering with evil humans, but when His patience runs out, He will use war and fire to destroy evil humans. Exodus 15:3 (KJB). The Devil also uses fire in his wars against God's people. But the Devil will use fire indiscriminately to kill evil people as well as good ones. The Devil hates the goodness that God puts into every human He creates. Genesis 1:31; Genesis 1:26-27 (KJB). The Devil hates God and anything God creates.
God revealed to Elisha that a servant of the king of Syria, named Hazael, would become the king of Syria and that he would commit some terrible atrocities against women and children. At first, Hazael did not believe Elisha, but when he returned to Syria, he evidently decided to give in to the evil nature inside of him, and so he murdered the king of Syria and became the king. He then fulfilled the prophecy of Elisha. II Kings 13:3 (KJB).
Hazael actually also destroyed many evil humans because many of the people of Israel at that time worshipped idols. In all wars, good and evil humans are both destroyed. God allows evil armies to destroy other evil armies because that diminishes evil in the world and that causes less suffering for the human race in the long run. Romans 9:28 (KJB). God also allows good people to be killed in wars to prove that no matter how brutal and cruel the Devil can be, he can never utterly destroy anything that God has created and loves. Ecclesiastes 3:14; I Corinthians 13:8 (KJB). God will recover and recreate absolutely everything He creates. Romans 11:36; Revelation 21:5 (KJB). The Devil knows that when he kills evil people, he also kills their good natures as well and that is what he seeks to permanently destroy.
God has a good reason to allow good people and evil people to be killed. God has determined that He will sort it all out, and He will make His final judgment in the end of the world. John 12:47-48 (KJB). When He was on the earth, Christ did not judge the world because He creates every good and living human in the history of mankind. Revelation 4:11 (KJB). Christ judged only the Devil and all evil on His cross. John 12:31-32 (KJB). Christ gained a complete victory over all sin, evil, spiritual death, and the Devil in His death, burial, and resurrection. I Timothy 1:10; Revelation 1:17-18; I John 3:8 (KJB). Therefore, Christ must forever save all of His living humans that He creates and loves, some by His grace, and all others in His final judgment in the end of the world. John 5:24; II Timothy 4:1 (KJB). Every human who has given their lives to the service of evil also has a good and living nature created by God. God intends to save that good and living nature from eternal death. In the end of the world, Christ will appear to all of His living humans "on the earth, and under the earth," and He will cause them all to repent and believe in Him as the Lamb of God their Savior so that He can use His fiery wrath against evil to dissolve their beings to separate their repentant, good and living natures for Him to recreate to live forever on His recreated earth, and He will cast their dead and evil natures into the eternal lake of fire. Revelation 5:11-14; II Peter 3:9-13; Revelation 20:5; Revelation 21:1-5; Revelation 22:11-12; Revelation 20:11-15 (KJB). II Peter 3:9 relates that God is "not willing that any should perish, but that all should come to repentance." This verse can only mean that Christ must forever save all of His living humans because His Will cannot be thwarted. I Timothy 2:4 (KJB).