The importance of money flows from it being a link between the present and the future.

Keynes’s remark frames money less as a mere medium of exchange than as a device for transferring purchasing power across time. Because production and consumption are separated by uncertainty, people value money for its liquidity: it can be held now and deployed later when needs, prices, or opportunities become clearer. In Keynesian terms, this “link between the present and the future” helps explain why saving can take the form of hoarding money rather than financing investment, and why expectations and confidence matter for employment and output. The line points toward his broader argument that monetary economies are governed by time, uncertainty, and the desire for security, not just by barter-like exchange.