Paul concludes this section with a brief summary of what the local church looks like, both corporately and individually. Questions like, how do I know I am a Christian, how do I know the Spirit is within me, and how do I know I am headed to heaven can all be answered in these 3 verses. How so? Because every Christian is filled with the Holy Spirit and verses 19-21 describe what being filled with the Holy Spirit looks like.
There are 4 ways that Paul gives for Christians to live a Spirit filled life. They are speaking to one another psalms, hymns, and spiritual songs, singing a joyous melody from the heart to the Lord, always giving thanks in everything, and being subject (or submitting) to one another. These all look different in the Christian life, but they are present nonetheless one way or another.
One critical note is that submission in verse 21 is what sets the remainder of chapter 5 in its proper context. A woman submits to a man the same way a brother and sister in Christ submit to one another. If a Christian is able to submit to one another, then what comes in the marriage relationship is that much simpler and easier to carry out.
