Then he said to Budila Âsvatarâsvi, 'O Vaiyâghrapadya, whom do you meditate on as the Self?' He replied: 'Water only, venerable king.' He said: 'The Self which you meditate on is the Vaisvânara Self, called Rayi (wealth). Therefore are you wealthy and flourishing.

In plain words: The king asks Budila what he worships as the Self, and he says water. The king says water is one part of the universal Self, called 'wealth.' That is why Budila is rich and thriving.