Karma is the law of moral causation.
While I don’t believe 100% in Buddhism, as I don’t know how I feel about “past lives” and all that, I quite strongly agree with the ideas that what we do and how we treat people will come back to haunt us in some way, shape, or form.
Be loving, because after all, the Golden Rule of (paraphrased here) “Do to others, what you would have done to you” is a concept embraced by multiple religions which on the majority of other topics vehemently disagree. If so many major religions agree on this one simple concept, don’t you think it just might be important?
I’m inclined to think so…
Buddhism: “Hurt not others in ways that you yourself would find hurtful.” Udana-Varga 5:18
Christianity: “Therefore all things whatsoever ye would that men should do to you, do ye even so to them: for this is the law and the prophets.” Matthew 7:12, King James Version.
Hinduism: This is the sum of duty: do not do to others what would cause pain if done to you.” Mahabharata 5:1517
Islam: “None of you [truly] believes until he wishes for his brother what he wishes for himself.” Number 13 of Imam “Al-Nawawi’s Forty Hadiths.”
Judaism: “What is hateful to you, do not to your fellow man. This is the law: all the rest is commentary.” Talmud, Shabbat 31a.