It depends on what you mean by Karma, first of all. If you are speaking of the Hindu/Buddhist karma, then that is the sum of all the good and bad deeds in your life, which separates from your physical body and the other parts that make you "you" at death, and joins up with another body and other parts to make a new "you" which then accumulates more karma. If you think that karma is just "what you do will be done to you", then that is fine, but it is not what karma really is. However, in reference to that Westernised karma belief, it doesn't work. Things do not even out. Hitler committed genocide. Millions of Jews, Romany, Christians, Poles, Russians and the disabled were murdered, and there has been no recompense fitting. Hitler is dead, so are his generals, but does that really make up for all the people they killed? Not at all. Justice has not been served. I believe in heaven and hell for good reason. Justice. God is perfectly just. Therefore his standards are perfect. No one with even a single sin can enter his presence (Heaven). In that way, heaven remains pure. So where does that leave humans? Of course, all of us have failed the standard. All of us deserve to spend eternity away from God (Hell). BUT God has worked out a way of satisfying justice AND letting fallen humanity into heaven. He sent his perfect Son as a sacrifice to PAY the penalty for sin (rebellion against God, disobedience, falling short of perfection). In that way, Jesus absorbed all the punishment, justice is satisfied, and (with Jesus as the stand-in) theoretically all humans can enter heaven. The only conditions are 1)recognise that you have fallen short of God's standards (ie sinned, disobeyed, rebelled) 2)ask forgiveness through the death of Jesus 3) trust that Jesus has the power over sin and death (by His resurrection) 3) surrender to Him totally God has promised a transformed heart to those who turn to Him. The door is open to everyone, no matter how sinful (disobedient, rebellious, egotistical, imperfect) they have been. Of course, there will be some who think they can get along quite fine without Jesus. they are the little Hitlers of this world, who don't defy God openly, but don't submit to Him either. The problem is: if you tell God over and over that you don't want Him, sooner or later, he will grant your desire, permanently. That is Hell, spending eternity regretting the bad decision you made not to follow him and enjoy the heaven he prepared for everyone.