When I think of the atrocities in the world, like the genocides of the 20th century, it makes me want to live my short life on earth with as few regrets as possible. Germans killing Jews during World War II (6 million); Turks killing Armenians, 1914-1915 (1.5 million); the Khmer Rouge killing Cambodians, 1975-1979 (2 million); Saddam Hussein's troops killing Iraqi Kurds, 1987-1988 (100,000); Serbs killing Bosnian Muslims, 1992-1995 (200,000); Hutus killing Tutsis, 1994 (800,000); Americans killing unborn children, 1973-present (40 million). Not to mention the 60 million people killed by the Communist regime mainly under Stalin. There were others.
Add to this the suffering owing to natural disasters like the tropical storm in November, 1970 that killed about 400,000 people in Bangladesh, or the earthquake of Gujarat, India in January, 2001 that killed 15,000, or the AIDS epidemic in Africa that has taken the lives of 2.5 million people. Then add the sadness and pain and eventual death of your own family. When I think on these things, it makes me tremble at the prospect of living a trivial, self-serving, comfortable, middle-class, ordinary, untroubled American life. I can't keep eternity out of my mind. Life is short and eternity is long. Very long. It is a long time to regret a wasted life.
Which raises the question: Is there regret in heaven? Can regret be part of the ever-increasing, unspeakable joy of the age to come, purchased by Jesus Christ (Romans 8:32)? My answer is yes. I am aware of promises like Revelation 21:4, "He will wipe away every tear from their eyes, and death shall be no more, neither shall there be mourning nor crying nor pain anymore, for the former things have passed away." But I don't think this rules out "tears of joy," and it may not rule out "regretful joy".
Why do I think this? I do not see how we will be able to worship Christ and sing the song of the Lamb without clear memory of the glorious, saving work of Jesus Christ and all that it involved. According to Revelation 5:9, the saints will sing "a new song, saying, 'Worthy are you to take the scroll and to open its seals, for you were slain, and by your blood you ransomed people for God from every tribe and language and people and nation.'" Ransomed from what? Will we have forgotten? This song and this memory will make no sense without the memory of sin. And the memory of sin will be hypocritical without the confession that it was our sin that Jesus died for.
It is inconceivable to me that we will remember our sin for what it really was, and the suffering of Christ for what it really was, and not feel "regretful joy." The intensity of our joy in grace will be fed by the remembrance of our unworthiness. He who is forgiven much, loves much (Luke 7:47). But this does not mean we should sin so that grace may abound (Romans 6:1). The holiest will be the happiest. But it does mean that regret will not ruin heaven. There will be kinds of joys, and complexities of happiness, and combinations of emotions in heaven of which we have never dreamed.
But all this leaves me trembling that I not throw away the one short life that I will look back on for all eternity. Just think of it. You have one life. One very short life. Then an eternity to remember. Does not the suffering in this world seem inexplicable to you? Is not this great global (and intensely personal) suffering a call to magnify the mercy of Christ by how we respond? Is not suffering a seamless fabric stretching into eternity for unbelievers? And therefore, are not Christians the only people who can respond with relief to the totality of misery?
Shall we not then live our lives - and prepare for heaven - by strategizing in all our vocations and with all our talents and all our money to relieve suffering (now and forever) for the glory of Jesus?