John “makes use of the strongest expressions for union with God that contemporary religious language provided, in order to assure his readers that he does seriously mean what he says: that through faith in Christ we may enter into a personal community of life with the eternal God, which is the character of
agape, which is essentially supernatural and not of this world, and yet planted firmly in this world, not only because real
agape cannot but express itself in practical conduct, but also because the crucial act of
agape was actually performed in history, on an April day about A.D. 30, at a supper-table in Jerusalem, in a garden across the Kidron valley, in the headquarters of Pontius Pilate, and on Roman cross at Golgotha. So concrete, so actual, is the nature of the divine
agape; yet none the less for that, by entering into the relation of
agape thus opened up for men, we may dwell in God and He in us.”
– C. H. Dodd (1963)
The Interpretation of the Fourth Gospel, Cambridge University Press, pp. 199-200, Greek transliterated.