Summary: Karma is as unbiblical as luck. Stop using that term.
John Lennon sang about “Instant Karma’s gonna get you” and even Christians will talk about Karma. Karma means deed or action and it is part of many beliefs in India as well as Taoism/Buddhism. Do you need to really worry about Karma? Karma is part of the belief that what we do here determines where we fall into the scheme of reincarnation. If you are a bad human things may not go well with you here, but if they do you cannot escape Karma because when you die you may come back as a cockroach instead of a human. If you have been a good human you may advance up the ladder until you reach the place where you then move out of that system and remain in a constant spiritual state.
My contact with Buddhism was in Thailand when I was stationed at Udorn Royal Thai AFB. One of the stories I was told involved two robbers who killed a baby and prayed to it for protection. Supposedly, the baby made them invisible to the police though other people could see them. I suspect the baby was grateful to them since they would move up the ladder because they died before they could do any evil. If they came back as a human, which would be most likely, their life would have no bad karma from the short life and would give them good karma. If they proceeded to live a better life then their next life would be even better and get them closer to the end of the process. My friends saw the baby as blessed but the robbers would be a mixed bag as they had some good karma by advancing the baby but bad karma because they were robbers making it interesting to how their next life would go.
There are universal principles put in place by God that all can observe and though all observe all have different interpretations. It is a universal law that if you plant corn you will get corn. If you properly prepare a field and tend to it you are going to get a harvest unless there is a drought or early freeze etc. Karma takes this principle and applies it to the soul as well.
2 Cor_9:6 But this I say, He which soweth sparingly shall reap also sparingly; and he which soweth bountifully shall reap also bountifully.
Gal_6:7 Be not deceived; God is not mocked: for whatsoever a man soweth, that shall he also reap.
God does use that universal law of reaping and sowing to teach us that what we do in life has consequences. Sow righteousness and your life will be fruitful and if you sow sin and iniquity you will reap sorrow and destruction. Yet, as we see in Scripture and in life it does not always look like it is a universal law. Some good people die young or suffer in this world while wicked people succeed and die in their old age surrounded by loved ones.
Psa 73:1 A Psalm of Asaph. Truly God is good to Israel, even to such as are of a clean heart.
2 But as for me, my feet were almost gone; my steps had well nigh slipped.
3 For I was envious at the foolish, when I saw the prosperity of the wicked.
4 For there are no bands in their death: but their strength is firm.
5 They are not in trouble as other men; neither are they plagued like other men.
The Psalmist noted this discrepancy and was ready to give up on God and His law because it seemed to be in vain. But read the rest of the psalm and you get the OT version of Jonathan Edward’s sermon “Sinners in the Hands of an Angry God.” The real harvest happens at death. We see this also in the parable of the rich man and Lazarus. In this life, it appeared that sowing and reaping was not working, but death is called the Grim Reaper and the rich man reaped his wild oats that he had sown and the poor man reaped Paradise.
You may be thinking that the folks that believe in Karma have it right. Sadly, no. They see what God instituted and misunderstood it. Karma may seem to match the concept of reaping what you sow, but it has no mercy or grace in it. In some cultures, if you are born into the poor group you have no means of rising above your status. Indeed, in some places the darker the skin the more dirty and unholy you are so even if you were born into a rich family you would still be shunned and considered evil. Your only hope is that you might progress in the next life.