SB 3.5.1

śrī-śuka uvāca
dvāri dyu-nadyā ṛṣabhaḥ kurūṇāṁ
 maitreyam āsīnam agādha-bodham
kṣattopasṛtyācyuta-bhāva-siddhaḥ
 papraccha sauśīlya-guṇābhitṛptaḥ
Synonyms: 
śrī-śukaḥ uvāca — Śukadeva Gosvāmī said; dvāri — at the source of; dyu-nadyāḥ — the celestial river Ganges; ṛṣabhaḥ — the best of the Kurus; kurūṇām — of the Kurus; maitreyam — unto Maitreya; āsīnam — sitting; agādha-bodham — of unfathomed knowledge; kṣattā — Vidura; upasṛtya — having approached nearer; acyuta — the infallible Lord; bhāva — character; siddhaḥ — perfect; papraccha — inquired; sauśīlya — gentleness; guṇa-abhitṛptaḥ — satisfied in transcendental qualities.
Translation: 
Śukadeva Gosvāmī said: Vidura, the best amongst the Kuru dynasty, who was perfect in devotional service to the Lord, thus reached the source of the celestial Ganges river [Hardwar], where Maitreya, the great, fathomless learned sage of the world, was seated. Vidura, who was perfect in gentleness and satisfied in transcendence, inquired from him.
Purport: 

Vidura was already perfect due to his unalloyed devotion to the infallible Lord. The Lord and the living entities are all qualitatively the same by nature, but the Lord is quantitatively much greater than any individual living entity. He is ever infallible, whereas the living entities are prone to fall under the illusory energy. Vidura had already surpassed the fallible nature of the living entity in conditional life due to his being acyuta-bhāva, or legitimately absorbed in the devotional service of the Lord. This stage of life is called acyuta-bhāva-siddha, or perfection by dint of devotional service. Anyone, therefore, who is absorbed in the devotional service of the Lord is a liberated soul and has all admirable qualities. The learned sage Maitreya was sitting in a solitary place on the bank of the Ganges at Hardwar, and Vidura, who was a perfect devotee of the Lord and possessed all good transcendental qualities, approached him for inquiry.