Karma is a concept that is derived from Buddhism and Hinduism. Proponents of this concept believe that a person would reap the things he did when he was alive, in the form of reincarnation. He may receive good things for the good he did, and bad things for the bad he has done.
Unfortunately, this exact concept cannot be found in the Bible as the word of God is clear that death only comes once to a human being. After this death, man would have to face the judgment in front of God. In karma, the judgment is applied when the person is reincarnated.
However, some people relate karma to the concept of sowing and reaping. This principle is indeed present in the Bible from the Old to the New Testaments. It is the natural course of things that sowing leads to a harvest, and laziness would lead to hunger. But there is nothing supernatural or spiritual with these realities.