Shishya (disciple) like the Sad-guru is really embodiment of Jnana.
The difference between the two lies in the attitude, high realization, marvellous super-human Sattva (beingness) and unrivalled capacity and Aishwarya Yoga (divine powers).
The Sad-guru is Nirguna, Sat-Chit-Ananda. He has indeed taken human form to elevate mankind and raise the world. But his real Nirguna nature is not destroyed thereby, even a bit. His beingness (or reality), divine power and widsom remain undiminished.
The disciple also is in fact of the same swarupa. But, it is overlaid by the effect of the samaskaras of innumerable births in the shape of ignorance, which hides from his view that he is Shuddha Chaitanya (see B.G. Ch. V-15). As stated therein, he gets the impressions – “Iam Jiva, a creature, humble and poor.”
The Guru has to root out these offshoots of ignorance and has to give upadesh or instruction.
To the disciple, held spell- bound for endless generations by the ideas of his being a creature, humble and poor, the Guru imparts in hundreds of births the teaching – “You are God, you are mighty and opulent.” Then, he realizes a bit that he is God really.
The perpetual delusion under which the disciple is labouring, that he is the body, that he is a creature (jiva) or ego, that God (Paramatma) and the world are different from him, is an error inherited from innumerable past births. From actions based on it, he has derived his joy, sorrows and mixtures of both.
To remove this delusion, this error, this root ignorance, he must start the inquiry.
How did the ignorance arise? Where is it? And to show him this, is called the Guru’s upadesh.
SSSC-Ch 29
"I draw to Me, My man from far off or even across the seven Seas to Shirdi, like a sparrow with a string fastened to its feet"-Shirdi Sai Baba, Indian Spiritual Guru-God 