We wish you all a Happy Guru Purnima
From the Shvetashvatara upanishad 6-23:
If one has supreme devotioni to Godi,
and for one's Guru as much as for God,
to this one these teachings (of self realization) which have been declared
may become manifest in a great soul,
yes, may become manifest in a great soul.
yasya deve paraa bhaktiH yathaa deve tathaa gurau .
tasyaite kathitaa hyarthaaH prakaashante mahaatmanaH .. 23..
prakaashante mahaatmana iti .
यस्य देवे परा भक्तिः यथा देवे तथा गुरौ ।
तस्यैते कथिता ह्यर्थाः प्रकाशन्ते महात्मनः ।। २३।।
प्रकाशन्ते महात्मन इति ।।
The day of worship of one’s preceptor, is a day of pure joy to the sincere spiritual aspirant. Thrilled by the expectation of offering his reverent homage to the beloved Guru, aspirants await this occasion with eagerness and devotion. It is the Guru alone that breaks the binding cords of attachment and releases the aspirant from the trammels of earthly existence....
The Srutis say: “To that high-souled aspirant, whose devotion to the Lord is great and whose devotion to his Guru is as great as that to the Lord, the secrets explained herein become illuminated”. Guru is Brahmanii, the Absolute, or God Himself. He guides and inspires you from the innermost core of your being. He is everywhere.
Have a new angle of vision. Behold the entire universe as the form of the Guru. See the guiding hand, the awakening voice, the illuminating touch of the Guru in every object in this creation. The whole world will now stand transformed before your changed vision. The world as Guru will reveal all the precious secrets of life to you, and bestow wisdom upon you. The supreme Guru, as manifested in visible nature, will teach you the most valuable lessons of life.
Please refer http://www.hinduism.8k.com/gurupurnima.html for details