SB 4.13.24

etad ākhyāhi me brahman
 sunīthātmaja-ceṣṭitam
śraddadhānāya bhaktāya
 tvaṁ parāvara-vittamaḥ
Synonyms: 
etat — all these; ākhyāhi — please describe; me — unto me; brahman — O great brāhmaṇa; sunīthā-ātmaja — of the son of Sunīthā, Vena; ceṣṭitam — activities; śraddadhānāya — faithful; bhaktāya — unto your devotee; tvam — you; para-avara — with past and future; vit-tamaḥ — well conversant.
Translation: 
Vidura requested Maitreya: My dear brāhmaṇa, you are well conversant with all subjects, both past and future. Therefore I wish to hear from you all the activities of King Vena. I am your faithful devotee, so please explain this.
Purport: 

Vidura accepted Maitreya as his spiritual master. A disciple always inquires from the spiritual master, and the spiritual master answers the question, provided the disciple is very gentle and devoted. Śrīla Viśvanātha Cakravartī Ṭhākura said that by the mercy of the spiritual master one is blessed with the mercy of the Supreme Lord. The spiritual master is not inclined to disclose all the secrets of transcendental science unless the disciple is very submissive and devoted. As stated in the Bhagavad-gītā, the process of receiving knowledge from the spiritual master entails submission, inquiry and service.