Sankaracarya's Vivekachudamani 431

लीनधीरपि जागर्ति जाग्रद्धर्मविवर्जितः ।

बोधो निर्वासनो यस्य स जीवन्मुक्त इष्यते ॥ ४२९ ॥

līnadhīrapi jāgarti jāgraddharmavivarjitaḥ |

bodho nirvāsano yasya sa jīvanmukta iṣyate ||

(Sankaracarya's Vivekachudamani 431)

One who has merged oneself in the Brahman yet is alert, but without the characteristics of wakefulness, whose Knowledge is free from desire, he is considered a jivan-mukta.

A person who is elevated, always meditating and his mind is fixed on the Lotus feet of Hari. Such a person is very rare in this world. Al his research and knowledge will be based on spiritual matters and understanding the Supreme Lord.

The surrendered person never forgets the Lord even a millisecond. He never thinks about enjoying this material world. Always think of himself as a servant of the Lord. That rare person free from all attachments and he is a liberated soul or Jivan Mukta.