Jesus, The Good Shepherd, made the following promise: "To those who listen to my voice and follow my direction, I will grant eternal life." What is this eternal life? Is it an endless form of what we now experience, though perhaps in another place and under better conditions? "No!"...says John, "this is eternal life, that they KNOW the one true God and Jesus Christ whom He has sent."
Since we already KNOW something about the Father and Jesus, it appears that eternal life begins here, in co-existence with temporal life. We can conclude then that heaven is not a place but rather a condition or a state of intimacy with God, in and through Jesus.
Now this, in turn, suggests a similar condition of unity joining together all of those who share the common condition of unity with Christ. In other words, if I am united to Christ and you are united to Christ, then, we have a common bond. We are, as Paul reminds us, brothers and sisters in Christ. We are brothers and sisters sharing, at this very moment, in the first stage of eternal life...a life over which death has no power. Because of this, I have no doubts about our being reunited with our loved ones after we die. Put simply, being united to each other through Christ in this life leads to our being consciously united to each other for all eternity.
Since it is in KNOWING and LOVING that we are said to be God's image, it only makes sense that heaven consists in knowing and loving God and each other to the fullest. This means that in heaven, truth and goodness will be the very essence of our lives.
But being creatures endowed with free will, we are capable of alienating ourselves from God...literally damning ourselves by what we choose to do or neglect to do. In the process, we also risk alienating ourselves from those who have opted for intimacy with God. That is Hell.
The split begins in this life and becomes permanent in the next. If heaven begins on earth, then so to does hell.
Now to qualify for hell, the alienation must be complete. Because of Christ's loving sacrifice, anything less than total alienation will ensure our ultimate salvation. In other words, you don't have to be all that good to get to heaven. "Thou hast made us for thyself and our hearts are restless until they rest in thee."
It is too bad that most of us are not a little keener to get to heaven. The problem seems to be that we know what makes us happy here on earth and we are not so sure that the purely spiritual versions of those joys will compare favourably. I do not say this lightly as it is a very real difficulty. It has been said that the hell of thinking about heaven is that we cannot imagine or trust a love that surpasses our own understanding. To which, I say, AMEN.