An “expedient” is a means to accomplish an end. When the intended goal is to do the Word of God, then an expedient is the vehicle, if you will, that is necessary for accomplishing the end of obedience to the Word. But if your goal is to get lots of people in the building, then raffles and loud music are expedients to accomplish it.
Now there might be several ways to accomplish the goal of obedience. And as long as any one of them does
not add to the Word by going beyond what is needed to accomplish the Word, it is permissible. The command of God is to go into all of the world. There are a number of ways that one may “go” and accomplish the command without going beyond what is the command. To get in a car, boat, plane, or simply to walk, all help to expedite the command to “go” without adding to the command.
In my post here I’m employing a bit of sarcasm, based on truth, to say that musical instruments are an expedient. But they are not an expedient to truth and spirit worship. Instead the goal is not “truth and spirit” worship because those who use musical instruments do not see in the Bible much in the way of guidance on what is acceptable for worship. So for them the goal is different. They follow the Old Testament and use that to justify their worship. Therefore musical instruments are an expedient to do that. They want to make good sounds and attract young people (think about Quail Springs church of Christ) and so a musical instrument is an expedient to accomplish that. When your goal is to appeal to peoples’ ears, musical instruments are an expedient to accomplish it. They stroke the senses. They vibrate the skin. They tickle the auditory nerves. They raise the hairs on the skin. They increase the heart rate and blood pressure. Mission accomplished.
But when the goal is to do what God says and to do no more, the church will sing.