Brihaspati

S’ûka then accepted Brihaspati as his guru and began devotedly, with his whole head and heart to perform duly the Brahmacharya vow (the life of studentship and celebacy). The Muni S’ûka remained in the house of his Guru and studied the four Vedas with their secrets and epitomes and all the other Dharma S'âstras and gave Daksinâ to the Guru duly according to proper rules, and returned home to his father Krisna Dvaipâyan.

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Sukdev to Vyas

When I studied first, the Veda in detail, it struck me that the Vedas dealt with the S'âstra of Karma mârga (the way of action); and it is all full of Himsâ (injury to others). 

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Then I took Brihaspati as my Guru to shew me the way to true wisdom; but soon I found that he, too, was attacked with the dreadful disease Avidyâ (ignorance) and plunged in the terrible ocean of world, full of Mâyâ. So it became quite clear to my mind, how could he save me? If the physician be diseased himself, how can he effect cures to other diseases? When I am desirous of liberation, how can I get it from a Guru who is himself deeply attached to the world; how can such a one treat my case to free me, from the disease of attachment to this world? It would be merely a farce. I bowed down to the Guru and now I am come to you to save me, frightened by this terrible serpent of Samsâra.

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Source

https://www.sacred-texts.com/hin/db/bk01ch14.htm