Dr, Kennedy on the innovations Arminians brought into worship to advance their gospel:
In connection with unscriptural devices resorted to in order to advance the movement, Dr. Kennedy mentions first excessive hymn-singing as one of these. “The singing of uninspired hymns even in moderation, as part of public worship, no one can prove to be scriptural; but the excess and the misdirection of the singing in this movement were irrational as well. Singing ought to be to the Lord; for singing is worship. But singing the gospel to men has taken the place of singing praise to God…. Many professed to have been converted by the hymns.
“The use of instrumental music was an additional novelty, pleasing to the kind of feeling that finds pleasure in a concert. To introduce what is so gratifying there, into the service of the house of God, is to make the latter palatable to those to whom spiritual worship is an offence. The organ-sounds effectively touch chords which nothing else would thrill….
“And yet it is not difficult to prove that the use of instrumental music, in the worship of God, is unscriptural, and that therefore all, who have subscribed to the [Westminster] Confession of Faith, are under solemn vow against it. There was a thorough change, in the mode of worship, effected by the revolution, which introduced the New Testament dispensation. So thorough is this change, that no part of the old ritual can be a precedent to us. For all parts of the service of the house of God there must be New Testament precept or example. No one will pretend that for instrumental music, in the worship of God, there is any authority in New Testament Scripture. ‘The fruit of the lips’ issuing from hearts that make ‘melody to the Lord,’ is the only form of praise it sanctions….
“But we use the organ only as an aid, it is said. ‘It is right that we should do our best in serving the Lord; and if the vocal music is improved by the instrumental accompaniment, then surely the organ may be used.’ On the same ground you might argue for the use of crucifixes and pictures, and for all the paraphernalia of the Popish ritual. ‘These,’ you might say, ‘make an impression on minds that would not otherwise be at all affected. They vividly present before worshippers the scenes described in Scripture, and if, as aids, they serve to do so, they surely cannot be wrong.’ To this, there are three replies, equally good against the argument for instrumental music. (1) they are not prescribed in New Testament Scripture, and therefore they must not be introduced into New Testament worship. (2) They are incongruous with the spirituality of the New Testament dispensation. (3) These additions but help to excite a state of feeling which militates against, instead of aiding, that which is produced by the Word. An organ may make an impression, but what is it but such as may be made more thoroughly at the opera? It may help to regulate the singing, but does God require this improvement? And whence arises the taste for it? It cannot be from the desire to make the praise more fervent and spiritual, for it only tends to take attention away from the heart, whose melody the Lord requires. It is the craving for pleasurable aesthetics, for the gratification of mere carnal feeling, that desires the thrill of organ sounds, to touch pleasingly the heart, that yields no response to what is spiritual. If the argument, against the use of the organ, in the service of praise, is good, it is, at least equally so against its use in the service of preaching. If anything did ‘vanish away,’ it is surely the use of all such accessories in connection with the exhibition of Christ to men. [Hebrews 8.]
~Rev. William MacLean, M.A., “Arminiamism: Another Gospel”