Complex sentence: What keeps man from this state of consciousness is the ego (also described as self-concept) the identification with a false self ultimately weakens through endless expression of itself in many lifetimes of experience, finally disappearing completely in full Self or God-realization.
Split into simpler sentences: What keeps man from this state of consciousness is the ego, the identification with a false self. Ultimately the ego weakens through endless expression of itself in many lifetimes of experience, finally disappearing completely in full Self or God-realization.