Your idea that the Teacher is the Overself is rarely found among Westerners but often among Orientals. But how can this be possible? What is the Overself? Answer this correctly and you will comprehend how impossible such an idea must be.
Go back to the hidden Ground of everything, the passive Mind or pure Being, the First, the unconditioned Origin of all. This is utterly inconceivable and unknowable. The very concept of it, this infinite mystery of mysteries, is so awesome that the little mind of man hesitates and trembles when it even approaches it in the deepest meditation. It is beyond the capacity of that mind to penetrate the reality behind the concept. A mediating principle is necessary here. This exists in the Overself, which is nothing more than a germ of that same infinite M I N D, although to the adventurous mystic it seems the unlimited End of all.
If this were not present in man, not only would mystical experience be impossible for him but all religious intuition would be mythical to him. This is the divinity within him, but it is only a spark. The fullness of the flame is with the Godhead alone.
This is why philosophy repudiates the Oriental notion which merges the human individual in God or the Occidental notion which identifies Jesus with God. In the first case, the merger is actually with the Overself. In the second case, his inner life took on a divine flavour; his mind entered a deep intimacy with the Overself. He was always conscious of the sacred presence in his heart. But even though Jesus came so much nearer to God than has the rest of mankind--with the exception of the other Masters--he still remained within the limits of human organization. Where Christian religion goes beyond such a claim it is the result of a mixture of unseeking ignorance and deliberate imposture. But in the earliest Christian circles, which had some pretense to culture, the truth was known. The name "Christos" or "Christ" meant man's higher self and was used in the same way that the term "Overself" is used today. "Jesus Christ" meant that the man Jesus had been "Christed" by becoming consciously fused and unified with his Overself.
Hence you may correctly say that the Teacher, Prophet, or Guide is a medium for the Overself. While he is still embodied, still using an intellect and body (an ego), he can only be a medium, not more. He is the Overself but working through, and therefore necessarily limited by, a human individuality. It is true that in the deepest rapt meditation he can divest himself of this individuality and become the pure Overself in awareness, but that is an unusual state and you must consider him as he is in ordinary life.
-- Notebooks Category 25: World-Mind in Individual Mind > Chapter 6 : Teaching Masters, Discipleship > # 200
