...go thou to the sea, and cast an hook, and take up the fish that first cometh up; and when thou hast opened his mouth, thou shalt find a piece of money: that take, and give unto them for me and thee. Matthew 17:27
A basic truth about the Christian life is that we serve a living Christ who is working in this world. Since this is a physical world He must use physical means to accomplish many of His goals. But that doesn’t mean He is tied to this world’s economic system. Jesus works in a different economic system. His economic system is displayed in this verse, and Christians can participate in this system.
First, there was a ministry need (demand). In this case it was payment of the annual temple tax which was owed by all Jewish men. But it could have been any of a number of other ministry needs. Jesus always has a plan to meet the demands of His ministry.
Next He gathered and prepared the raw materials to meet the need (supply). In this case a fish and a coin. Jesus didn’t comment on how he prepared the fish, but I suspect He used physical means to get the coin into the fish’s mouth. The fish serve him too.
Third, Jesus used human labor and expertise. Peter, a fisherman by trade, was sent to get the prepared materials (a coin) to meet this ministry need. Peter was also compensated for his labor when his taxes were paid with the same coin. The means were physical, but the power behind the means was Jesus.
Fourth, Jesus again used human labor to complete the work. In this case he used Peter to take the coin to the tax-collectors. The need could have been any number of things including giving the Gospel, but the economics are the same. Get involved in what Jesus is doing and experience His economy. His demand is always met by His supply.