… in Mandukya Upanishad (text),
“When you look at the sun, you behold your own eye. When you look above into the heavens, you are seeing your own head. When you see all people moving about, you behold the various parts of your own personality. The vast wind is your breath. All your actions are cosmic movements. Anything that moves, does so on account of your movement. Your breath is the Cosmic Vital Force. Your intelligence is the Cosmic Intelligence. Your existence is Cosmic Existence. Your happiness is Cosmic Bliss.”
Therefore, a person with an understanding of Mandukya Upanishad looks at each and every object/human as a part of self, thereby converting all the objects into one subject, hence leading to cosmic union.
In other words: Hate for others is reflective of hate for yourself and love for others is reflective of love for oneself.