I believe in heaven because Jesus believed in heaven. Also because C..S. Lewis said it best:
Just read this fascinating article about a doctor who was in coma, got to see the after life and his reports of it.
The Bible talks a lot about heaven. Here are some verses.
Psalm 23:4
Even though I walk through the valley of the shadow of death, I will fear no evil, for you are with me; your rod and your staff, they comfort me. (NIV)
1 Corinthians 15:54-57
Then, when our dying bodies have been transformed into bodies that will never die, this Scripture will be fulfilled:
“Death is swallowed up in victory.
O death, where is your victory?
O death, where is your sting?”
For sin is the sting that results in death, and the law gives sin its power. But thank God! He gives us victory over sin and death through our Lord Jesus Christ.(NLT)
2 Corinthians 5:8
Yes, we are fully confident, and we would rather be away from these earthly bodies, for then we will be at home with the Lord.(NLT)
Philippians 1:22-23
But if I live, I can do more fruitful work for Christ. So I really don’t know which is better. I’m torn between two desires: I long to go and be with Christ, which would be far better for me.(NLT)
Believers will dwell with God forever.
Psalm 23:6
Surely goodness and love will follow me all the days of my life, and I will dwell in the house of the LORD forever.(NIV)
Also:
1 Thessalonians 4:13-18
Jesus prepares a special place for believers in heaven.
John 14:1-3
“Do not let your hearts be troubled. Trust in God; trust also in me. In my Father’s house are many rooms; if it were not so, I would have told you. I am going there to prepare a place for you. And if I go and prepare a place for you, I will come back and take you to be with me that you also may be where I am.”(NIV)
Philippians 1:21
For to me, to live is Christ and to die is gain. (NIV)
Revelation 14:13
And I heard a voice from heaven saying, “Write this down: Blessed are those who die in the Lord from now on. Yes, says the Spirit, they are blessed indeed, for they will rest from their hard work; for their good deeds follow them!” (NLT)
Philippians 3:20-21
But our citizenship is in heaven. And we eagerly await a Savior from there, the Lord Jesus Christ, who, by the power that enables him to bring everything under his control, will transform our lowly bodies so that they will be like his glorious body. (NIV)
After their physical death, believers gain eternal life.
John 11:25-26
Jesus said to her, “I am the resurrection and the life. He who believes in me will live, even though he dies; and whoever lives and believes in me will never die. Do you believe this?” (NIV)
Revelation 21:1-4
Then I saw a new heaven and a new earth, for the first heaven and the first earth had passed away … I saw the Holy City, the new Jerusalem, coming down out of heaven from God … And I heard a loud voice from the throne saying, “Now the dwelling of God is with men, and he will live with them. They will be his people, and God himself will be with them and be their God. He will wipe every tear from their eyes. There will be no more death or mourning or crying or pain, for the old order of things has passed away.” (NIV)
1 Corinthians 15:50-53
I declare to you, brothers, that flesh and blood cannot inherit the kingdom of God, nor does the perishable inherit the imperishable. Listen, I tell you a mystery: We will not all sleep, but we will all be changed—in a flash, in the twinkling of an eye, at the last trumpet. For the trumpet will sound, the dead will be raised imperishable, and we will be changed. For the perishable must clothe itself with the imperishable, and the mortal with immortality. (NIV)