God As Spirit in Ancient Judaism? (John 4:24)

One Christian disciple recorded Jesus the Jew proclaiming that God is spirit: "God is spirit, and those who worship him must worship in spirit and truth." (John 4:24, ESV)

Is there an equivalent speech act uttered about YHWH (Jehovah) in the Hebrew Bible? What about Isaiah 31:3 (ESV)?

"The Egyptians are man, and not God, and their horses are flesh, and not spirit. When the Lord stretches out his hand,
the helper will stumble, and he who is helped will fall, and they will all perish together."

Notice the contrast made between humans and God, who is spirit. Admittedly, ancient Judaism likely did not make a sharp distinction between outward worship and inward spirituality, especially as we witness some people doing today: ("I'm spiritual, but I'm not religious"). Yet, neither was Jesus criticizing all Jewish rituals when he spoke the words at John 4:24, but he was suggesting that in the future, God's people would not chiefly focus on ritualistic externals nor would they emphasize a specific earthly city like Jerusalem. Why would this change occur? Because God is a spirit.

C.K. Barrett writes (The Gospel According to St. John, page 238): There is little corresponding teaching in the Old Testament (cf. however Isa. 31.3: The Egyptians are men, and not God; and their horses flesh ( . . . basar), and not spirit (. . . ruah); significantly this contrast does not appear in the LXX): Spirit in the Old Testament is regularly not an order of being over against matter, but life-giving, creative activity, and there are passages (e.g. 7.38f.) where John uses the word in this sense.

Jesus was not condemning all outward expressions of worship: he was a son of the commandment, a devout Jew, and God's shaliach. The Lord knew that the Mosaic Law prescribed certain rituals, so he would not have called the entire Jewish system into question. But Jesus did call first-century Jews to repentance; furthermore, by Jesus' time, there was not one form of Judaism being practiced but many "Judaisms" as Jacob Neusner observed. First-century Judaism (to borrow a phrase) had a "dizzying diversity" of beliefs and practices.

So what did Jesus mean at John 4:23-24 when he proclaimed that God's true worshipers would worship him in spirit and in truth? Here is one suggestion given by Barrett (page 239):

It is impossible to separate the two notions (note that neither in v. 24 nor in v. 23 is EN repeated before ALHQEIA). EN PNEUMATI [dative-gk.] draws attention to the supernatural life that Christians enjoy, and EN ALHQEIA [dative-gk.] to the single basis of this supernatural life in Christ through whom God's will is faithfully fulfilled. That true worship is set over against idolatry, and over against a cult restricted to one sanctuary, is not more than incidental.

EGF: