Sankaracarya's Vivekachudamani 452

न नभो घटयोगेन सुरागन्धेन लिप्यते ।

तथात्मोपाधियोगेन तद्धर्मैर्नैव लिप्यते ॥

na nabho ghaṭayogena surāgandhena lipyate |

tathātmopādhiyogena taddharmairnaiva lipyate ||

(Sankaracarya's Vivekachudamani 452)

Space, because of its contact with the jar, is not tainted by the smell of the liquor in it. So too, the Self is not affected by the attributes of the conditioning adjuncts (upadhis) because of its contact with them. 

 Although the air may have the smell of liquor when it comes in contact with a liquor jar, it never is contaminated. Similarly a pure will never become contaminated with the material world, although he gets in touch with materialistic people. Such a rare people are eligible for becoming a guru and attain the Lord.