Commenting on John 4:24, New Testament scholar, C.H. Dodd wrote:
It should be observed that to translate 'God is a spirit' is the most gross perversion of the meaning. 'A spirit' implies one of the class of πνευματα, and as we have seen, there is no trace in the Fourth Gospel of the vulgar conception of a multitude of πνευματα. (C.H. Dodd, The Interpretation of the Fourth Gospel [Cambridge: 1958], 225 n. 1)
On the absurdities of understanding John 4:24 as teaching the ontological nature of God, Origen wrote:
Many writers have made various affirmations about God and His ουσια. Some have said that He is of a corporeal nature, fine and aether-like; some that he is of incorporeal nature; others that He is beyond ουσια in dignity and power. It is therefore worth our while to see whether we have in the Scriptures starting-points (αφορμας) for making any statement about the ουσια of God. Here [1 John i.2] it is said that πνευμα is, as it were, His ουσια. For he said, πνευμα ο θεος. In the Law He is said to be fire, for it is written, ο θεος ημων πυρ καταναλισκον (Deut. iv.24, Heb. xii. 29), and in John to be light, for he says, ο θεος πως εστι, και σκοτια εω αυτω ουκ εστιν ουδεμια (1 John i.5). if we are to take these statements at their face value, without concerning ourselves with anything beyond the verbal expression, it is time for us to say that God is σωμα; but what absurdities would follow if we said so, few realise. (Origen, Commentary on John xiii.21-23, as cited by Dodd, ibid., 225-26).
Note: Origen in this passage understood it unwise to appeal to John 4:24 "at face value" to support God not being embodied, notwithstanding his use of such a verse in On First Principles to support God not having a body. Origen is not a witness for divine embodiment, but only a witness that early Christians, including those who would use John 4:24 as evidence that the Father does not have a body, would not go "beyond what is written" about this text (Origen is, sadly, very complex, in comparison to other early Christian authors).
This is mirrored by the comments of Raymond Brown in his magisterial 2-volume commentary on John's Gospel:
This is mirrored by the comments of Raymond Brown in his magisterial 2-volume commentary on John's Gospel:
[This verse is] not an essential definition of God, but a description of God's dealing with men; it means that God is Spirit toward men because He gives the Spirit (xiv 16) which begets them anew. There are two other such descriptions in the Johannine writings: "God is light" (1 John i 5), and "God is love" ( 1 John iv 8 ). These too refer to the God who acts; God gives the world His Son, the light of the world (iii 19, viii 12, ix 5) as a sign of His love (iii 16). (The Gospel According to John (i-xii), vol. 29 of the Anchor Bible [Garden City, N.Y.: Doubleday, 1966], 167.)