PULPIT COMMENTARY ON JOHN 4:24
Verse 24. A still more explicit and comprehensive reason is given for the previous assertion, based on the essential nature of God himself in the fulness of his eternal Being. God is Spirit (Πνεῦμα ὁ Θεός; cf. John 1:1 (http://biblehub.com/john/11.htm), Θεὸς η΅ν ὁ Λόγος, the article indicates the subject, and the predicate is here generic, and not an indefinite; therefore we do not render it, "God is a Spirit"). The most comprehensive and far-reaching metaphor or method by which Jesus endeavoured to portray the fundamental essence of the Divine Being is "Spirit," not body, not ὕλη, not κόσμος, but that deep inner verity presented in self-conscious ego; the substantia of which mind may be predicated, and all its states and faculties. The Father is Spirit, the Son is Spirit, and Spirit is the unity of the Father and the Son. St. John has recorded elsewhere that "God is Light," and "God is Love." These three Divine utterances are the sublimest ever formed to express the metaphysical, intellectual, and moral essence of the Deity. They are unfathomably deep, and quite inexhaustible in their suggestions, and yet they are not too profound for even a little child or a poor Samaritaness to grasp for practical purposes. If God be Spirit, then they who worship him, the Spirit, mustby the nature of the case, must by the force of a Divine arrangement, worship him, if they worship him at all, in spirit and in truth. The truth which our Lord uttered was not unknown in the Old Testament. From Genesis to Malachi, in the Psalms, in the historical books, in Judges, Samuel, and Kings, the Spirit and the spirituality of God are presupposed; but the Lord has generalized these teachings, cited them from darkness and neglect, combined them in one eternal oracle of Divine truth. The Galilaean Peasant has thus uttered the profoundest truth of ethic and religion one which no sage in East or West had ever surpassed, and towards which the highest minds in all the ages of Christendom have been slowly making approach. Forms, postures, ceremonial, sacraments, liturgies, holy days, and places are not condemned, but they all are inefficacious if this prime condition be not present, and they can all be dispensed with if it be. Only the spirit of man can really touch or commune with the Spirit of spirits, and the history of the new dispensation is the history of a progress from forms to realities, from the sensuous to the spiritual, from the outward to the inward, from the earthly to the heavenly