The Holy Spirit gives us the power to overcome the sin that we carry around within us because we still live in bodies contaminated by sin. This is the purpose of the Spirit's filling. To help you understand and appropriate the reality of this, let me make five observations about the exciting, powerful, yet often misunderstood verse we're reading today.
First, Paul is definitely talking about yielding control of your will to another. The drunk yields to alcohol. We are to yield to the Spirit. That's a big difference, but the principle is the same in each case.
Second, notice that the positive statement is a command. Paul is not saying, “If you'd like to, it would be nice if you were filled with the Spirit.” He is saying that if you are going to please God, then you must be filled with His Spirit.
Third, this is a plural command. It applies to every believer. The Spirit's fullness is not for the elite few. There are Christians you may look at and say, “If I could just be like them. They love Jesus so much, and they walk so closely with Him. Why can't I be like that?” You can. The difference is the filling of the Spirit, not the fact that they have something you don't.
Fourth, this plural command is also passive. You can't fill yourself. This is the sovereign activity of the Spirit. That means your attempts to fill yourself are going to be very unfulfilling.
Fifth, this plural, passive command is also present tense, meaning it is a continuous action. You don't get filled today and expect it to cover you tomorrow, just like you don't eat Sunday dinner and expect it to carry you to next Sunday. The Holy Spirit's filling is a dynamic, moment-by-moment experience.