People have different ideas about heaven. Many have no understanding of God at all, but still like to think of heaven as the "better place" where we all go when we die. Most people don't give heaven much thought until they attend a funeral or a loved one dies.
But the Bible has a lot to say about life after death, and it contradicts popular opinion. John 3:16 says, "For God so loved the world that he gave his one and only Son, that whoever believes in him shall not perish but have eternal life." Then in verse 36, Jesus goes on to say, "Whoever believes in the Son has eternal life, but whoever rejects the Son will not see life, for God’s wrath remains on them." Hebrews 9:27 says, "It is appointed to men once to die, but after this the judgment." According to these verses, everyone dies, but not everyone goes to heaven (Matthew 25:46; Romans 6:23; Luke 12:5; Mark 9:43).
God is holy and perfect. Heaven, His dwelling place, is holy and perfect, too (Psalm 68:5; Nehemiah 1:5; Revelation 11:19). According to Romans 3:10, "there is none righteous, no not one." No human being is holy and perfect enough for heaven. The people we call "good" are not good at all compared to the sinless perfection of God. If God allowed sinful humans to enter the perfection of heaven, it would no longer be perfect. What standard should be used to determine who is "good enough?" God's standard is the only one that counts, and He has already ruled. Romans 3:23 says that "all have sinned and fallen short of God's glory." And the payment for that sin is eternal separation from God (Romans 6:23).
Sin has to be punished, or God is not just (2 Thessalonians 1:6). The judgment we face at death is simply God bringing our accounts up to date and passing sentence on our crimes against Him. We have no way to make our wrongs right. Our good does not outweigh our bad. One sin ruins perfection, just as one drop of arsenic in a glass of water poisons the whole glass.
When we stand before God one day, we cannot beg entrance to heaven based on our own merit. We have none to offer. Compared to God's standard of holiness, not one of us is good enough. But Jesus is, and it is by His merit we can enter heaven. First Corinthians 6:9-11 says, "Do you not know that wrongdoers will not inherit the kingdom of God? Do not be deceived: Neither the sexually immoral nor idolaters nor adulterers nor men who have sex with men nor thieves nor the greedy nor drunkards nor slanderers nor swindlers will inherit the kingdom of God. And that is what many of us were. But by repentance you were washed, you were sanctified, you were justified in the name of the Lord Jesus Christ and by the Spirit of our God." The sacrifice of Jesus covers it all.
The people who go to heaven are all alike in one way: they are sinners who have placed their faith in the Lord Jesus Christ (John 1:12; Acts 16:31; Romans 10:9). They have recognized their need for a Savior and humbly accepted God's offer of forgiveness. They have repented of their old ways of living and set their course to follow Christ (Mark 8:34; John 15:14). They have not attempted to earn God's forgiveness but have served him gladly from grateful hearts (Psalm 100:2). The kind of faith that saves a soul is one that transforms a life (James 2:26; 1 John 3:9-10) and rests fully on the grace of God.