Chandogya Upanishad
Prapathaka IV, Khanda 2
Then Gânasruti Pautrâyana took six hundred cows, a necklace, and a carriage with mules, went to Raikva and said:
'Raikva, here are six hundred cows, a necklace, and a carriage with mules; teach me the deity which you worship.'
The other replied: 'Fie, necklace and carriage be thine, O Sûdra, together with the cows.' Then Gânasruti Pautrâyana took again a thousand cows, a necklace, a carriage with mules, and his own daughter, and went to him.
He said to him: 'Raikva, there are a thousand cows, a necklace, a carriage with mules, this wife, and this village in which thou dwellest. Sir, teach me!'