[manoDev]

Working with the promise of a future promotion is, effectively, giving credit to your employer.

"In every country in which the capitalist mode of production reigns, it is the custom not to pay for labour-power before it has been exercised for the period fixed by the contract, as for example, the end of each week. In all cases, therefore, the use-value of the labour-power is advanced to the capitalist: the labourer allows the buyer to consume it before he receives payment of the price; he everywhere gives credit to the capitalist."

- Karl Marx. Capital Volume One, Chapter Six: The Buying and Selling of Labour-Power.