Justin Martyr ... "The use of singing with instrumental music was not received in the Christian churches as it was among the Jews in their infant state, but only the use of plain song ... Musical organs pertain to the Jewish ceremonies and agree no more to us than circumcision."
Clement of Alexandria ... "Leave the pipe to the shepherd, the flute to the men who are in fear of gods and are intent on their idol-worshipping. Such musical instruments must be excluded from our wineless feasts ... 'Praise Him with harp,' for the tongue is a harp of the Lord; 'and with the lute, praise Him,' understanding the mouth as a lute moved by the Spirit ... But for us to make use of one instrument alone: only the Word of peace, by whom we pay homage to God, no longer with ancient harp or trumpet or drum or flute.
What trumpet of God is now heard--unless it is in the entertainments of the heretics? (Tertullian, c. 210)
Why should I speak of strings set vibrating to noise? Even if these things were not dedicated to idols, they should not be approached and gazed upon by faithful Christians. (Novatian, c. 235)
The unison voices of Christians would be more acceptable to God than any musical instrument. Accordingly in all the churches of God, united in soul and attitude, with one mind and in agreement of faith and piety we send up a unison melody in the words of the Psalms. (Eusebius, Commentary on Psalm 91:2-3, c.320)
Chrysostom ... "It was only permitted to the Jews, as sacrifice was, for the heaviness and grossness of their souls. God condescended to their weakness, because they were lately drawn off from idols: but now instead of organs, we may use our own bodies to praise him withal."
Augustine ... "Praise the Lord with harp; sing unto Him with the psaltery of ten strings,' For this even now we sang, this expressing with one mouth, we instructed your hearts. Hath not the institution of these Vigils in the name of Christ brought it to pass that harps should be banished out of this place? ... Let none turn his heart to instruments of the theatre."
The Council of Laodicea (367) forbids the use of musical instruments in worship, and this has remained the policy of the Eastern Orthodox Church to the present day. In 416 the Council of Carthage addressed this issue and declared, "On the Lord's day let all instruments of music be silenced."
Thomas Aquinas wrote, "Our church does not use musical instruments, as harps and psalteries, to praise God withal, that she may not seem to Judaize."
John Calvin, in his "Commentary on Exodus," 15:20, writes, "Instrumental music is reckoned among the number of legal ceremonies which Christ hath abolished, where as now we must retain a gospel simplicity."
The Synod of Holland and Zealand, convened in 1554, gave the following instruction:
"That ministers should endeavour to prevail with the magistrates to banish organs and instrumental music out of the churches." Twenty-seven years later, in 1581, the National Assembly convened in Middleburg, again called for the removal of organs from the churches. Therefore, those who champion the use of instrumental music in Christian worship are in direct opposition to the Apostolic Simplicity of Worship as held by the fathers of the Dutch Reformation."
Even the Catholics admit this: "For almost a thousand years Gregorian chant, without any instrumental or harmonic addition, was the only music connection with the liturgy. The organ, in its primitive and rude form, was the first, and for a long time the sole, instrument used to accompany the chant. It gave the pitch to the singers and added brilliancy and sonority. (Instruments which replaced the songs were strongly condemned). Catholic Encyclopaedia online.
John Calvin, “Musical instruments in celebrating the praises of God would be no more suitable than the burning of incense, the lighting of lamps, and the restoration of the other shadows of the law. The Papists, therefore, have foolishly borrowed this, as well as many other things from the Jew. Men who are fond of outward pomp may delight in that noise: but the simplicity which God recommends to us by the apostles is far more pleasing to Him.” (Commentary on Psalms 33)
John Wesley, “I have no opposition to the organ in our chapel provided it is neither seen nor heard.” (Adam Clark’s Commentary, Volume 4, page 868)
Adam Clark, “I am an old man, and an old minister; and I here declare that I never knew them to be productive of any good in the worship of God; and have had reason to believe that they were productive of much evil. Music, as a science, I esteem and admire; but instruments of music in the house of God I abominate and abhor.” (Adam Clark’s Commentary, Volume 4, page 686)
Charles Spurgeon, when asked why, in the twenty years he preached in London, never used the organ in worship, cited 1 Cor. 14:15 and said “I will pray with the spirit and I will pray with the understanding also, I will sing with the spirit, and I will sing with the understanding also. I would as soon pray to God with machinery as to sing to God with machinery.”
Finally,
James W. McKinnon examined 150 references to Christian music up to the Middle Ages and found opposition to instruments ‘uniform, vehement, and monolithic’.