Heaven
Not clouds and harps, but a renewed world and the face of God
Ask most people what heaven is and you get some version of the same picture: disembodied souls drifting on clouds, strumming harps, in an endless and frankly rather boring church service in the sky. It is worth saying clearly that this picture is almost the opposite of what the Bible actually promises. The biblical hope is not less physical than this life but more, not escape from the world but its healing, not the end of our humanity but its completion. Heaven, rightly understood, is the most solid and earthy hope there is, and the dull caricature has done real damage by making the best news in the world sound tedious.
First, where the dead in Christ are now
The Bible does speak of a present heaven, where those who have died in Christ are with Him now, conscious and at peace, awaiting the resurrection. Paul says to depart this life is "to be with Christ; which is far better" (Philippians 1:23), and "to be absent from the body, and to be present with the Lord" (2 Corinthians 5:8). Jesus told the dying thief, "To day shalt thou be with me in paradise" (Luke 23:43). This is real comfort for grief: the believer who dies is not annihilated and not asleep in nothing, but with the Lord. Yet the New Testament treats even this blessed state as an intermediate one, not the final hope. The best is still ahead, and it is bodily.
The real hope: resurrection and a new creation
The Christian hope has always been, in the words of the creed, "the resurrection of the body, and the life everlasting." We are not meant to stay disembodied spirits forever; we are promised new, glorified, physical bodies like the risen Christ's, who Himself ate and was touched after He rose (see the resurrection). And those bodies need a world. So the last vision in the Bible is not of us flying up to a misty heaven but of heaven coming down to a renewed earth: "I saw a new heaven and a new earth," and "the tabernacle of God is with men, and he will dwell with them" (Revelation 21:1-3). The whole groaning creation is to be set free, "delivered from the bondage of corruption" (Romans 8:21). The God who made matter and called it good does not finally scrap it. He makes it new.
Every tear wiped away
What will the new creation be like? The Bible is restrained, but its central promise is the removal of every evil that has ever made us weep. "God shall wipe away all tears from their eyes; and there shall be no more death, neither sorrow, nor crying, neither shall there be any more pain: for the former things are passed away" (Revelation 21:4). Read that slowly, because every word of it is a funeral undone: no more death, no more of the grief that has broken us, no more pain in the body or the mind. And the One on the throne stakes His own character on it: "Behold, I make all things new" (Revelation 21:5). Not all new things, but all things new, the very world we know, mended.
The joy at the center: God Himself
It is possible to want heaven for everything except the one thing that makes it heaven. The deepest joy of the new creation is not its streets or its reunions, wonderful as those are; it is God Himself, seen at last face to face. "Now we see through a glass, darkly; but then face to face" (1 Corinthians 13:12); "they shall see his face" (Revelation 22:4); "we shall be like him; for we shall see him as he is" (1 John 3:2). This is what older Christians called the beatific vision, and it is the true heaven of heaven. Every good thing we have ever loved was a beam coming from that Sun; in the end we get the Sun. A heaven full of gifts but empty of God would not be heaven at all, and a heaven with God needs nothing added to it.
People sometimes dismiss heaven as wishful escapism, a way of ignoring this world while waiting for the next. History suggests the reverse. It is precisely the people most convinced of the world to come who have built hospitals, freed slaves, and stayed in plague cities to nurse the dying, because they had nothing left to lose and a hope nothing could take. As C.S. Lewis observed, the Christians who did the most for the present world were those who thought most of the next (see C.S. Lewis). A hope that the world will be healed, and that no good done in it is ever wasted, does not make you idle. It makes you brave. The new earth is not a reason to abandon this one; it is the promise that this one matters enough to be redeemed.
Where this lands
Heaven is not a consolation prize for people too weak to face reality; it is reality finally come into its own, the world unbroken, the body raised, the tears wiped, and God in the midst of His people forever. It is the home you have been homesick for without a name to put to it, the place every earthly joy was quietly pointing toward. And the way in is a Person. Jesus said it to friends afraid of the future: "In my Father's house are many mansions… I go to prepare a place for you" (John 14:2-3). The door is already opened by the cross and the empty tomb; the invitation is to come to Him now, and one day to come home (see the resurrection that guarantees it, and the God who is its joy).
Related: The Resurrection, The Judgment, Hell, The Character of God, Last Things, and C.S. Lewis. Scripture from the King James Version, linked to BibleHub; the words of God are marked in gold, the words of Christ in purple.