1-58-18 Sanskrit Verse
Adi Parva - Book One
Na ca s`uudra samaabhyaashee
King Janameejaya asked Vais`ampaayana: "Why the celestial Gods took birth on Earth?". Vais`ampaayana explained to him the benevolent environment prevailing at that time and how it subsequently became polluted. The pollution and domination of sin required the Lord Vishnu and celestial Gods to take births on Earth for the purpose of killing demons and sinful kings.
ENGLISH GIST OF 1-58-18 QUOTED ABOVE
Vedas were not being read in the presence of Sudras.
Not reading Vedas in the presence of the 4th caste persons was taken as an indication of good rule and environment.
*The Mahabharata times were extremely unkind to the fourth caste in the hierarchy (S`udras). The fourth caste was not only prevented from learning Vedas, but also the Priests were so apprehensive that they did not read Vedas when the Fourth Caste persons were present.