The Supreme Personality of Godhead expands Himself by svāṁśa (His personal expansions) and vibhinnāṁśa (His expansions as the living entities). As stated in Bhagavad-gītā (4.8), paritrāṇāya sādhūnāṁ vināśāya ca duṣkṛtām: the Supreme Personality of Godhead appears on this planet for the protection of the sādhus, or devotees, and for the destruction of the miscreants, or nondevotees. He especially descends to give protection to the cows, the brāhmaṇas, the demigods, the devotees and the Vedic system of religion. Thus He appears in various forms — sometimes as a fish, sometimes a boar, sometimes Nṛsiṁhadeva, sometimes Vāmanadeva and so on — but in any form or incarnation, although He comes within the atmosphere of the material modes of nature, He is unaffected. This is a sign of His supreme controlling power. Although He comes within the material atmosphere, māyā cannot touch Him. Therefore, no material qualities can be attributed to Him in any degree.