Let’s take a look at an interesting little measuring device. You probably have several of them—each designed for a specific job. I am referring to the thermometer. You may have one to tell you the temperature outside. Another tells you how warm it is in the house. Another is used to determine whether your body temperature is normal. Still others are used in cooking.

The thermometer is a useful measuring tool, but that’s as far as it goes. It tells you the condition, but it can’t do a thing about it.

But there is another device in your home that goes the second step. It not only knows the temperature in your home, but depending on how you adjust it, it will also take appropriate action to make a change occur. If it’s too cool in your house, it will turn the furnace on and keep it on until the desired temperature is reached. If it’s too warm, this clever device—called a thermostat—will bring the air conditioner on for as long as it takes to cool your place down.

Did you know that there are “thermometer Christians” and “thermostat Christians”? Thermometer Christians can tell you what needs to be done. They know someone must take the gospel to the lost. They know someone must disciple the children. They know their neighbors need to hear about Jesus. They know someone must maintain the church building. They know someone must finance it all. They even know their own spiritual condition. But they seem incapable of doing anything about those things.

Thermostat Christians know someone must take the gospel to the lost, and they go do it. Or, they support those who do, by prayer and giving. They know someone must disciple the children, and they go do it (or they support those who do). They know their neighbors need to hear about Jesus, so they go next door and tell them. They know someone must maintain the church building, and they go do it. They know someone must finance it all, and they do it.

A third device that you may have in your home is called a rheostat. This little dandy is used to adjust the brightness of a light fixture. If the adjustment knob is turned way down, the light is very dim. As the knob is turned, the light gets brighter. In other words, the rheostat limits the amount of electricity reaching the light bulb. Unfortunately, a rheostat doesn’t save much electricity because when it is turned down it absorbs the power that could be flowing to the light bulb and wastes it by getting hot.