The following is an article by Stephen Barber.
Bishop Kallistos Ware once memorably described Williams’s account of heaven as the place of exchange. He summed it up by drawing on a phrase Williams quotes in ‘Bors to Elayne: on the King’s Coins’:
This is the way of this world in the day of that other’s;
make yourselves friends by means of the riches of iniquity,
for the wealth of the self is the health of the self exchanged.
What saith Heracleitus? – and what is the City’s breath? –
dying each other’s life, living each other’s death.
Money is a medium of exchange.
In one of his few notes, Williams gives his source: ‘The quotation from Heracleitus was taken from Mr. Yeats’s book, A Vision.’ This is a little terse, and it is worth following through in more detail.