We established what gets a person into heaven isn't just the fact Jesus forgave our sins, but that their spirit has been re-created by the Holy Spirit. The issue in God's mind is the nature of the human spirit.
While some recoil in horror at the thought of good people spending eternity in hell, and others say you can live however you like and still end up in heaven, to understand heaven and hell we need to ask: Why is there a hell in the first place? And: How could a God of love send people to hell?
Why is there a hell?
We read Romans 1:20 that says the invisible things of God are reflected in the physical creation, but we don't understand the depth of that truth. The physical creation mirrors the spirit realm because the unseen spiritual realm created the visible universe. (Hebrews 11:3)
We need to go back in time when only God and angels existed. Only God's presence filled everything - not yet stars, nor planets, nor anything of this physical realm - just God's realm existed.
There was a cherub named Lucifer. Cherubs are described in The Revelation 4:6-8, Ezekiel 1:5-13 and Isaiah 6:2-3 as multi-winged angelic beings who are around the Father's throne and worship saying, "Holy, holy, holy, is the Lord of hosts; the whole earth is full of His glory" and "Holy, holy, holy, Lord God Almighty, who was, and is, and is to come." Isaiah calls them 'Seraphs', which is Hebrew for 'burning ones', to describe their appearance when they move and fly, but they are cherubs by classification and not separate beings. (See also Ezekiel 28: 14-18, Isaiah 14:12-15)
Lucifer had some authority and wanted to be God. We understand he led a rebellion that involved 1/3 of the angels. We are only given glimpses of these events, but Revelation 12:7-8 says this: "And there was war in heaven. Michael and his angels fought against the dragon, and the dragon fought and his angels. But he did not win; neither was there found a place for him any more in heaven."
Lucifer getting kicked out of heaven is the first record of cause and effect, the first record of one being held accountable for one's actions. The first record of actions having consequences, perhaps unintended consequences from Lucifer's perspective, yet consequences still. And it all occurred in the Spirit realm.
We understand the Spirit realm created the physical universe, so physical laws of cause and effect exist because spiritual laws of cause and effect first existed.
When the physical laws come into play, like when one asteroid bumps into another and sends that one careening through space, or when you kick a ball and send it through the air, those laws of motion are in effect because Lucifer rose up in one direction against God and was cast out in the opposite direction.
Whether that be the lone zebra that wanders from the herd and faces the consequences of being attacked by lions, or a child touching a hot stove, or a person having an affair and not thinking through the hurt and pain and loss they and their loved ones would experience, or a person spending tens of thousands in credit cards and facing years of digging themselves out of debt, consequences of actions is how the universe is put together. And it all started with God holding Lucifer accountable for his actions way back when.
The fact a law of the universe is that for every action there is an equal and opposite reaction, is a form of judgement built into the universe. It is immediate consequence and responsibility for an action. When you hit that guy in grade school and he hit you back was a sample of immediate judgement by action. When you ate too much and got heartburn, your body judged your overeating and gave you the consequences.
Though some physical consequences aren't seen for years, like decades of smoking only late in life causing health issues, judgement comes - we are held accountable for our actions, for what we've sown, one way or the other - that's the universe.
People are Confused
People think when they get themselves into great debt or get ill after decades of abusing their bodies (for example), all they have to do is ask God to give them money or heal them. But they don't realize the Bible lays out two issues: The vertical, which is our walk with God. And the horizontal, which is our walk in this world.
You can repent for spending yourself into the poor house, or repent for clogging your arteries all those years, which takes care of the vertical, but it takes real work facing the consequences of your actions and walking out new actions because for God to miraculously bail you out every time would violate foundational physical and spiritual laws of action/reaction and accountability.
If you repent vertically you won't be held accountable to God spiritually because you judged yourself now. But the consequences in the physical are manifested/judged on earth. To paraphrase what Paul said in I Corinthians 6:18 in a principle larger than the single example he gave; sins in the body are manifest in the body. Meaning, sins of the earth are judged and dealt with on the earth: the body, finances, relationships, etc.
Yet God is merciful
In Matthew 25:41 Jesus tells us what He will say to the unsaved people at judgement, speaking of Himself in the 3rd person as the King: "Then He will say to those on his left hand, 'Depart from me you cursed ones, into everlasting fire, which was prepared for the devil and his angels.'"
Notice the everlasting fire was originally prepared for the devil and his angels but people go into it as well. It was prepared because spirit beings are eternal so cannot cease to exist, and neither Satan nor those people want God nor His presence.
So to answer the questions at the start, there is a hell because #1, all the universe is held accountable for its actions, and #2 (how can God send people to hell): God in His great mercy has provided for people and fallen angels what they want - a place without Him. No love, no peace, no joy - which are all attributes of God. He always provides a way of escape, and for those who don't want Him, that is their way out.
Next week we'll look at love and boundaries, the kingdom of hell, is it eternal, what it is like, the ranks and order and such, and also what happens to Christians who turn the grace of God into a license for sin. Until then, Blessings,