Hurting others is sin. When you hurt others, it is based on your feeling that the other is different from you — different in religion, nationality, race, and so on. In other words, you do not feel a sense of oneness with the other. “The feeling of oneness is deﬁned as love. We love our family members because we feel a sense of oneness with them.”(Source: Building a Noble World).
Our sages have said, “Know thyself.” What is self? Self means “I am.” If you add anything after “I am,” such as “I am so and so” — I am man, I am woman, I am rich, that is not the true self. Where does the true self reside? Below is my response, taken from the link to my previous answer on Quora: Shiv Jhawar’s answer to Why is meditation tough for me?
“In waking, we use the physical body, mind, and prana (breath or vital force). In dreaming, we use mind and prana; we no longer use the physical body. In deep sleep, we use only the prana; we no longer use the physical body and mind. The turiya or fourth both permeates and transcends the three states of mind — waking, dreaming, and deep sleep. The fourth is not a state really; it is pure awareness of the Self. The turiya is where the true Self resides.”
When you turn inward and dive deep within your own self, you are going to experience true consciousness — call it atman in Sanskrit, true self, spirit, energy, or being. It is then you will realize that true consciousness, the highest form of energy, of each human being is identical to every other human being. It is different from the three states of mind — waking, dreaming, and deep sleep.
It is impossible to divide true consciousness, which is akin to the sky. For example, you can have a Hindu/Christian/Muslim mind, but you cannot have a Hindu/Christian/Muslim consciousness.
As you experience your own being as pure consciousness, you will naturally feel that other people are a part of the same pure consciousness, leading you to naturally love others, not hurt others. Lord Jesus said, “Love your neighbor as you love yourself,” meaning, feel the consciousness of the other individual as your own consciousness.
In reality, the true self is the self of all, but it is not felt in this way. The illusion of being separate is the root cause of violence, conflict, and suffering in the world. Despite differences in forms, the original source — the formless stream of consciousness — is one and the same. To grasp this point, imagine three wells. These wells all look different from the outside but their source — the stream of water flowing into each well — is one and the same. In the same way, individuals may look and think differently, but their true self is the self of all.
If one does not even know one’s own true self, how can one ever come to know anybody else’s true self? Indeed, the ignorance of one’s own true self leads to hurting others.