Paul commanded the Ephesians to be filled by the Spirit (Eph. 5:18, lit. trans.). I take “filled” to be a reference to the work of the Spirit in supplying us with a greater (experiential?) understanding of the fullness of God in our lives. One of the means (or results, depending on how you take the participles) is congregational singing– “singing to one another”. Paul gives three categories: psalms, hymns and spiritual songs. Without going into a lot of detail, I believe that the psalms are the psalms of the OT, the hymns are various texts like we see in the NT (i.e., Col. 1:15-18), and spiritual songs are any other songs that aren’t found in the canon.
That said, have you noticed that very little of the first two categories of songs are actually heard in our congregations? Thankfully Bob Kauflin and the guys at Sovereign Grace have a new CD out called “Psalms“. Here are twelve songs based on the text of the Psalms that would be a great start for your churches. I pray that there will be more songs like the ones on this CD and others like “His Love Endures Forever” (Chris Tomlin, based on Psalm 136), “Better Is One Day” (Matt Redman, based on Psalm 84), and others that are actually striving to use the texts of Scripture. What a great way to memorize Scripture, and what a great way to encourage and admonish your fellow congregants so that they are filled with the fullness of God. Keep writing! Keep singing!