19 speaking to one another in psalms and hymns and spiritual songs, singing and making melody in your heart to the Lord,
The first half of verse 19 is corporate worship, but the second half is personal worship.
singing and making melody
The second result of being filled with the Spirit is personally worshiping the Lord in music.
“Singing” is vocal, whereas “making melody” is using musical instruments to accompany the singing. The New Testament always uses the term “singing” for praising God (Co 3:16; Re 5:9; 14:3; 15:3).
“Making melody” means literally to pluck with a stringed instrument; however, it metaphorically means to make music by instruments.
in your heart
It is not enough to sing with our vocal cords; true spirituality sings with the “heart” (1 Co 14:15). Spirit-filled believers manifest their spirituality in their hearts. The Holy Spirit puts a song in our hearts. Singing with our lips is one thing, but singing with our heart is another.
to the Lord,
The focus of spiritual music directs itself to the Lord, to our Lord Jesus Christ. The purpose of music is to glorify the Father and the Son.
The believer is to minister to the Lord with the heart.
A Spirit-filled Christian sings with other believers and worships God with music. Music is a sign of being controlled by the Spirit. It is a manifestation of joy within. We truly have a song to sing because of our worthy Lord.
Ps 33:1, Rejoice in the Lord, O you righteous! For praise from the upright is beautiful.