Chandogya Upanishad 1.8

There were once three men, well-versed in udgîtha, Silaka Sâlâvatya, Kaikitâyana Dâlbhya, and Pravâhana Gaivali. They said: 'We are well-versed in udgîtha. Let us have a discussion on udgîtha.'

They all agreed and sat down. Then Pravâhana Gaivali said: 'Sirs, do you both speak first, for I wish to hear what two Brâhmanas have to say.'

Then Silaka Sâlâvatya said to Kaikitâyana Dâlbhya: 'Let me ask you.' 'Ask,' he replied.

'What is the origin of the Sâman?' 'Tone (svara),' he replied. 'What is the origin of tone?' 'Breath,' he replied. 'What is the origin of breath?' 'Food,' he replied. 'What is the origin of food?' 'Water,' he replied.

'What is the origin of water?' 'That world (heaven),' he replied. 'And what is the origin of that world?'— He replied: 'Let no man carry the Sâman beyond the world of svarga (heaven). We place (recognise) the Sâman in the world of svarga, for the Sâman is extolled as svarga (heaven).'

Then said Silaka Sâlâvatya to Kaikitâyana Dâlbhya: 'O Dâlbhya, thy Sâman is not firmly established. And if any one were to say, Your head shall fall off (if you be wrong), surely your head would now fall.'

'Well then, let me know this from you, Sir,' said Dâlbhya. 'Know it,' replied Silaka Sâlâvatya. 'What is the origin of that world (heaven)?' 'This world,' he replied. 'And what is the origin of this world?'— He replied: 'Let no man carry the Sâman beyond this world as its rest. We place the Sâman in this world as its rest, for the Sâman is extolled as rest.'

Then said Pravâhana Gaivali to Silaka Sâlâvatya: 'Your Sâman (the earth), O Sâlâvatya, has an end. And if any one were to say, Your head shall fall off (if you be wrong), surely your head would now fall.' 'Well then, let me know this from you, Sir,' said Sâlâvatya. 'Know it,' replied Gaivali.