The surface meaning of this statement by Ramana Maharshi is straightforward: to understand that every living creature shares a fundamental unity with your own Self. It suggests a feeling of interconnectedness, a recognition that the boundaries we perceive between ourselves and others are ultimately illusory.

However, within the Advaita Vedanta tradition, of which Ramana Maharshi was a preeminent exponent, this concept of oneness points to something far more radical. It is not merely an emotional or intellectual acknowledgment of unity, but the direct, experiential realization of Brahman, the Absolute Reality, as your own true nature – the Atman. The "Self" Ramana speaks of is not the individual ego or personality, but the formless, unchanging consciousness that is the substratum of all phenomena. The "oneness" is the dissolution of the illusion of separateness (maya), revealing that the perceived multiplicity of the world is, in truth, the singular, undifferentiated Self. This realization is the ultimate goal, the cessation of suffering arising from ignorance of this fundamental truth.

In your life: Practice observing the common threads of consciousness and experience that bind you to others, even those with whom you feel most distant, to begin dismantling the illusion of separation.