First, the users of money trust the issuing authorities to issue a reasonable quantity of dummies through its proper channels. Inversely, the initial issuance is a promise by the technicians of the technical rules governing issuance that they are working in good faith to cause neither inflation nor deflation. Second, the users of money in the form of credit implicitly promise to return full value to make the issuer whole in any transaction.
Thus the issuance and use of money is based on promises and trust. In this aspect, money is an instrument of convenience based upon promises and trust between people.
Money is not a commodity. It is a lubricating dummy qualified for exchange by trust among people in the exchange economy.