But the hour cometh, and now is, when the true worshippers shall worship the Father in spirit and in truth: for the Father seeketh such to worship him. God is a Spirit: and they that worship him must worship him in spirit and in truth. (John 4:23-24)

The “worship wars” always rage. Everyone has a different idea of what “worship” is. Praise bands or organs. What “holy days” we keep. How we administer sacraments. What the sermon and sanctuary should look like.

In a way, whenever we get into these discussions, we are getting bogged down in a discussion about carnal worship. We are asking questions regarding what “we think” worship should look like and what earthly things we will change to appease the senses – the sounds, the sights, the excitement, etc. As such, this takes us back into the types and shadows of which Christ has pointed to himself and out from which Christ has brought us. What did it mean when Hosea said (and Christ taught to understand the meaning of the words): “For I desired mercy, and not sacrifice; and the knowledge of God more than burnt offerings.” We see here that the earthly sacrifices revealed something greater; those who did them fulfilled a deeper command to worship God according to spiritual principles. No man could make his sacrifice and say “there, I did it” and leave aside the spiritual reality to which they point.

God’s worship is spiritual. We worship Him according to spiritual principles. But this begs the question: where do we learn these spiritual principles? We are left with a choice. We either are called to determine this on our own or God has left us principles to determine how He is to be worshipped.

This is the basis for what is often called The Regulative Principle of Worship.

This means that God has stated how He is to be worshipped in His word. By doing this, we may not – like any other portion of His word – add onto it, subtract from it, or change it in any way. He has given a positive command. When Christ says “Do this, in remembrance of me” at the Last Supper; does that mean we may not do it? Of course we must say that Christ has given us a command for worship. So we can prove that there is at least some principle by which God desires to be worshipped.

Now, of course, some disagree with how that principle is applied. That is a matter of exegesis, discernment, and prayer. However, we as Christians dedicated to the notion of Sola Scriptura should be the first to say that God has left all things necessary for not only our salvation, not only our knowledge of Him, but also for the worship of Him. The Westminster Confession states that the reason we translate the Scriptures in the first place is so that people everywhere may have the “Word of God dwelling plentifully” in them, and thus “they may worship Him in an acceptable manner.”

This demonstrates (among other places in Scripture and the Confession) that worship is according to the Scriptures. Christ, having done away with types and shadows, has cast aside the carnal forms of worship of previous times and has instituted a form more simple and spiritual.

Calvin says this on this passage:

Thus we may justly say that the worship of the Law was spiritual in its substance, but, in respect of its form, it was somewhat earthly and carnal; for the whole of that economy, the reality of which is now fully manifested, consisted of shadows.

We now see what the Jews had in common with us, and in what respect they differed from us. In all ages God wished to be worshipped by faith, prayer, thanksgiving, purity of heart, and innocence of life; and at no time did he delight in any other sacrifices. But under the Law there were various additions, so that the spirit and truth were concealed under forms and shadows, whereas, now that the vail of the temple has been rent, (Matthew 27:51,) nothing is hidden or obscure. There are indeed among ourselves, in the present day, some outward exercises of godliness, which our weakness renders necessary, but such is the moderation and sobriety of them, that they do not obscure the plain truth of Christ. In short, what was exhibited to the fathers under figures and shadows is now openly displayed. – Commentary on John 4

Also, Matthew Poole comments:

God is not a corporeal being, made up of blood, and flesh, and bones, having senses as bodies have, to be pleased with sensible things; but he is a spiritual Being, the Father of spirits, and requireth a spiritual service proportioned to his being; and therefore those that pay a religious homage to him, must do it with their spirits, and according to the rule that he hath prescribed, in truth and reality. This is now the will of God; and though he required of his people under the law a more ritual, figurative service, yet that is now to cease; and therefore the woman of Samaria need not trouble herself which was the truest worship, that at Mount Gerizim, or at Mount Zion, for both of them were very suddenly to determine, and a new and more substantial spiritual worship was to succeed, to the learning of the way and method of which she was more to attend, and not to spend her thoughts about these things which were of no significance, and tended only to minister questions of no use.  – Commentary on John 4

I am a Reformed Presbyterian. I offer all content as my own personal reflections. I am not a licensed minister.