It is an amazing thing that there are those who profess to know the Bible, yet who contend that God has left man free to improvise his own worship system. Like Jeroboam, the son of Nebat (1 Kings 12:25-33), they are innovators.
The early church was not without its problems with persons of this philosophy. In Philippians 3:1ff, Paul calls attention to certain individuals who were troubling the saints in Philippi. That these apostates had a Judaistic inclination is clear from Paul’s use of “concision” (a word-play hinting of circumcision), and his affirmation that “we are the circumcision,” i.e., the genuine Israel (cf. Romans 2:28,29; Galatians 6:16).
Underline “circumcision” and comment in your margin: Spiritual Israel. See Romans 2:28,29; Galatians 6:16.
The apostle then affirms that the faithful “worship by the Spirit of God.” The phrase “by the Spirit of God” denotes by the instruction of the Holy Spirit — as such is effected through the word of God (Ephesians 6:17).
The passage parallels John 4:24 in sentiment, which affirms that worship must be regulated by the truth, the depository of which is Scripture (John 17:17).
Thus, in your margin beside this verse write: Regulated worship; cf. Ephesians 6:17; John 4:24; 17:17.
An additional reference which you might wish to include is Colossians 2:23 — a passage condemning “will-worship.” Will-worship is worship which is either forbidden, or unbidden (W.E. Vine, Expository Dictionary, IV, p. 236).