The Guru performs the roles....

gururbrahma gururvishnuh gururdevo maheshvarah

guruh sakshat param brahma tasmai shri gurave namah

The Guru performs the roles of Brahma, Vishnu and Mahesh. Playing the role of Brahma, he gives us the jnana or knowledge. As Vishnu he protects that knowledge; and as Shankar or Mahesh he destroys or dispels ignorance.

This is the reason why the Guru is called Brahma, Vishnu and Sadashiva-all three in one. But no scholar has interpreted the above epithet in this way. All of them simply say that the Guru is Brahma, Vishnu and Mahesh and leave at that. They do not say how he is Brahma, how he is Vishnu and how he is Mahesh or in other words what exactly he does as such.

In fact, as Brahma he gives you knowledge. You know that Brahma is the creator of the universe. So he creates in us the knowledge of hitherto unknown things.

Vishnu is the protector and preserver of what has been created. So as Vishnu the Guru protects that 

knowledge otherwise it will disappear forever. Again as Vishnu the Guru through his repeated teachings instills knowledge into us again and again so that it is retained in our mind.

And when that knowledge is well-protected, the Guru will then assume the role of Shankar and destroy ignorance. When that happens we will have achieved our cherished goal!

 
Jagadguru Shri Kripalu Ji Maharaj...