The following scriptures were written to churches in the first century that relate to singing.
“Speaking to one another in psalms and hymns and spiritual songs, singing and making melody in your heart to the Lord.” (Ephesians 5:19 -NKJV)
From these scriptures, music has its place and purpose in the worship of the church. But what kind of music is authorized. Generally, music can be vocal, instrumental, or both. With no other scripture to rely upon after the church was established, we conclude that God specified the vocal music – singing. Since “singing” is specific, it excludes all other kinds of music. There is not a command, an example or a necessary inference for use of an instrument in our worship to God.
“Let the word of Christ dwell in you richly in all wisdom, teaching and admonishing one another in psalms and hymns and spiritual songs, singing with grace in you hearts to the Lord.” (Colossians 3:16 -NKJV)
“…I will sing with the spirit, and I will also singing with the understanding.” (1 Corinthians 14:15 -NKJV)
We, speaking of men, cannot add to or change what God has specified. We have many examples in the Bible where God specified one thing but man either added to it or changed it to their own peril.
From the above scriptures, we learn that singing serves a purpose. Scriptural singing is to teach and admonish one another, and to praise and give thanksgiving to God. While singing in worship is pleasing to our ears, the scriptures do not teach that singing is for entertainment.
From the scriptures above, the manner of singing is made clear. We are to sing songs with our lips, to God based upon the words of Christ, having grace in our hearts, and with an understanding of the sentiments of the songs. Instruments of music cannot teach, cannot admonish, and cannot “speak”, since the tune or melody of a song cannot do these things.
From the scriptures above, the kinds of songs are specified - psalms, hymns and spiritual songs which are focused on Scriptures. Songs for worship excludes the “popular”, “patriotic”, and “romantic” songs of our day which can have a place in our lives, but not in our worship.
Lastly, we do not use a choir. From the Scriptures above, the terms, "speaking to one another...in songs," and "admonishing one another...in songs. Each member has a responsibility for these actions. Again, there is not a scripture or an example in the New Testament for using a subgroup within the church to do the speaking and admonishing in songs for the congregation.