Śrīmad-Bhāgavatam 1.13.9

Vidura went out from the palace to detach himself from household affairs, especially political intrigues. As referred to hereinbefore, he was practically insulted by Duryodhana's calling him a son of a śūdrāṇī, although it was not out of place to talk loosely in the case of one's grandmother. Vidura's mother, although a śūdrāṇī, was the grandmother of Duryodhana, and funny talks are sometimes allowed between grandmother and grandchildren. But because the remark was an actual fact, it was unpalatable talk to Vidura, and it was accepted as a direct insult. He therefore decided to quit his paternal house and prepare for the renounced order of life. This preparatory stage is called vānaprastha-āśrama, or retired life for traveling and visiting the holy places on the surface of the earth. In the holy places of India, like Vṛndāvana, Hardwar, Jagannātha Purī, and Prayāga, there are many great devotees, and there are still free kitchen houses for persons who desire to advance spiritually. Mahārāja Yudhiṣṭhira was inquisitive to learn whether Vidura maintained himself by the mercy of the free kitchen houses (chatras).