Hell is the default destination for humanity. Because we fall short of God's standard (this is called sin) we cannot dwell in His presence (Matthew 25:41–46; Romans 6:23). This is hell.
Why does God send people to hell?
We are all created to exist eternally. It is up to us, our choice, whether to remain in rebellion to God and suffer eternal separation from Him (hell), or choose His way to avoid hell and live with Him eternally (heaven).
Hell was initially prepared for Satan and the angels who followed him in rebellion, but people who fail to choose salvation will be found there, too (Matthew 25:41; Romans 6:23).
God is perfectly righteous and moral (Psalm 18:30; 1 John 1:5). When we don't live up to His standards, and we cannot, it is called sin (Romans 3:23). We all have a sinful nature (Romans 5:12) and are born dead in sin (Ephesians 2:1–9). We are separated from God and also continually choose separation from Him (James 1:13–16). On earth, this is rebellion against God. In the afterlife, this is called hell.
God sends people to hell because He would not be just if He did not (Psalm 7:11). Like an earthly judge who does not punish the convicted, God would be unjust if He did the same (Deuteronomy 32:4).
However, as God is just, He is also full of mercy. Because of His character of mercy, and His love for people, He designed a way for people to avoid hell. He sent His Son, Jesus Christ to take our punishment for us (Ephesians 2:8–9; Romans 6:23; 10:9; John 3:16–18). When we accept Jesus' sacrifice on the cross as a substitute for our own (1 Peter 2:24), believe His statements about His divinity, and agree with Him about our sin, we can avoid hell. More than that, we can receive true life (John 10:10; Romans 6:23).
Who will go to hell?
Is hell fair?
Why are so many repulsed by the idea of eternal damnation?
How can I be sure that when I die I will go to heaven?
How can I be saved?
Truth about Eternity