Sankaracarya's Vivekachudamani 556

शैलूषो वेषसद्भावा भावयोश्च यथा पुमान् ।

तथैव ब्रह्मविच्छ्रेष्ठः सदा ब्रह्मैव नापरः ॥

śailūṣo veṣasadbhāvā bhāvayośca yathā pumān |

tathaiva brahmavicchreṣṭhaḥ sadā brahmaiva nāparaḥ ||

(Sankaracarya's Vivekachudamani 556)

Just as an actor, whether he wears the dress of his role or not, is always the same person, so too, the perfect knower of Brahman is always Brahman.

Although the Supreme Personality of Godhead takes various avatars, the qualities in his every avatar never change. Just like an actor changes his dresses but the actor remains the same. One who possess these Bhaga qualities is known as Bhagavan. And the following verses after it identify Bhagavan as Vãsudeva. Thus from this, we can know Lord Possesses six Auspicious qualities (Kalyana Guna) as Complete splendor, virtue, glory, opulence, knowledge, dispassion - these six are known as Bhaga. There is no one who can claim the six auspicious qualities. Only one sole proprietor for all those qualities, he is the Supreme Lord Bhagavan, Paramatma, and Brahman.