“Either Way, We Must Sing and Sing Only”
David B. Smith
"Psallo is one of five plural participles in Ephesians 5:19-21, used to explain how a person is to be “filled with the Spirit” [or as it is paralleled in Col. 3:16, to “let the word dwell in one richly”]. The five participles are speaking, singing, making melody, giving thanks and submitting. In Ephesians 5:19, psallo is translated “making melody.” Unfortunately, some people abuse the term in an effort to justify the use of instrumental music in worship. In fact some corrupted versions of the Bible completely disregard the meaning of the term, like the Amplified Bible which reads “offering praise with voices [and instruments]...” Such abuses go far in showing the lack of regard many translators have for the inspiration of the Bible.
"Psallo (Greek) is the New Testament equivalent to the Old Testament zamar (Hebrew). But even in the Old Testament, the word zamar did not inherently mean “to use the instrument.” The context determined whether the instrument was included. It is only used figuratively in the New Testament. And all credible translators know that it is only correct to translate the term into something like “making melody.” Lexicographers agree on this point. The object of the verb would decide whether the instrument was intended. And in Ephesians 5:19, there are only two options – neither of which authorizes natural or mechanical instruments of music:
"1. If the phrase is taken locatively, it means that making melody occurs “in the heart.” In such a case, melody is restricted to this one location, since 'specific action commands' exclude all other actions.
"2. If the phrase is taken in the instrumental case, it means that making melody occurs “with the heart.” In such a case, the heart is the only tool God allows for the making of the melody.
"Herein is the beauty of the phrase, as it appears in the Bible: the meaning is the same regardless. Either way, the songs must be sung and the melody must be made in the heart of man and with the heart of man. To use a play on words, the heart is the only authorized instrument. There can be no other conclusion but this.
"So when saints come together and blend their voices in song, they can be confident that they are accomplishing exactly what God requires for this act of worship without addition or subtraction. And this is the key to true worship (John 4:23-24), which goes before God as a sweet smelling savor."
https://www.thelordsway.com/SODDYDAISYTN/doclib/psallo.pdf
