“If even soulless instruments, such as the flute or the harp, do not give distinct notes, how will anyone know what is played? For if the trumpet makes an uncertain sound, who will prepare for battle?” (1 Cor. 14:7-8, emp. added).
“Likewise also with yourselves, if through another language you give not a meaningful word, how will one know what is said? For you will be speaking into the air” (1 Cor. 14:9, emp. added).
“What am I to do? I will pray with my spirit, but I will pray with my mind also; I will make melody with my spirit, but I will make melody with my mind also” (1 Cor 14:15).
“Otherwise, if you give thanks with your spirit, how can anyone in the position of an outsider say ‘Amen’ to your thanksgiving when he does not know what you are saying? For you may be giving thanks well enough, but the other person is not being built up” (1 Cor 14:16–17).
“Nevertheless, in assembly I would rather speak five words with my mind in order to instruct others, than ten thousand words in another language” (1 Cor 14:19).
“For God is not the author of confusion but of peace, as in all the assemblies of the saints” (1 Cor 14:33, emp. added).
“If anyone thinks himself to be a prophet or spiritual, let him acknowledge that the things which I write to you are the commandments of the Lord” (1 Cor 14:37).
“Let all things be done decently and in order” (1 Cor 14:40).
The Breath of God 
Let’s see….grape juice is soulless. Saltines are soulless. What else is soulless that we use as “instruments” toward acceptable worship? collection plates, pews, tables…….
The pitch pipe is soulless. Song books are soulless, etc. Hmmmm!
Romans 14:14 I know, and am persuaded by the Lord Jesus, that there is nothing unclean of itself: but to him that esteemeth any thing to be unclean, to him it is unclean.
This would include Instrumental Music.