When Vidura was invited by his elder brother [Dhṛtarāṣṭra] for consultation, he entered the house and gave instructions which were exactly to the point. His advice is well known, and instructions by Vidura are approved by expert ministers of state.
Srimad Bhagavata Purana
श्रीमद्भागवतमहापुराणम्
मूल श्लोकः
यदोपहूतो भवनं प्रविष्टो मन्त्राय पृष्टः किल पूर्वजेन । अथाह तन्मन्त्रदृशां वरीयान् यन्मन्त्रिणो वैदुरिकं वदन्ति
yadopahūto bhavanaṃ praviṣṭo mantrāya pṛṣṭaḥ kila pūrvajena | athāha tanmantradṛśāṃ varīyān yanmantriṇo vaidurikaṃ vadanti
SB 3.1.10