The great general lexicographers, from H. Stephens to Liddell and Scott, give not only "laver" but "bath," and hence washing and even water for bathing or washing. See the amplest proof in classic Greek given by Passow, Rost, Palm, etc. So Schleusner, Wahl, and Rose's "Parkhurst," among those devoted to the Greek New Testament. Indeed the LXX use in general a different word (λουτήρ) for a laver, and λουτρόν for washing, as in Cant. 4:2; 6:5. So the Apocryphal Sirax or Ecclesiastic. 31:25. (Ed. Tisch., 1850, vol. 2, p. 195.) Further, λουτρών was used for the bath as a place for washing; λουτρόν or λούτριον for the water rendered impure by bathing. See Scapula, Hederic, etc. Hence the English version is thoroughly justified, instead of its being "a meaning the word never has." It is generally, says Pape, cleansing, washing away of filth, abwaschen, abspülen. It may take, as a secondary meaning, the bath itself, as the word "bath" does in English. But it means applying the water, not the vessel. It is used often by the fathers for baptism, but even there in the same sense (ὡς ἐκπλυσίν, says Gregory Nazianzen). Indeed so far from being or alluding to a vessel, it is not likely a vessel was ever used in scriptural times. At any rate, Dean Alford's statement is quite unfounded. Titus 3 refers to baptism, but to washing, not to a font. A. says, See Lexx.; but the Lexx. give bath, water for washing or bathing, the act of washing, and even drink-offerings. It is not the bath properly as a place, but the bathing; and hence we have λουτρὰ θερμὰ and ψυχρὰ, λουτρά ὠκεανοῖο, and λουτρὰ φαινομένα ἐπὶ τῆς γῆς, etc. So the λουτροφόρος used to bring the water, not the bath as a vessel.
Next, while it may be right to connect ἐν ῥ. with the verb or the participle, we must necessarily connect τῶ λ. τοῦ ὕδατος too, and ἐν ῤ. becomes characteristic of the cleansing by the washing of the water. Thus this is the instrument of cleansing, and its true character is ῥῆμα. Neither of the constructions said to be required in this case is called for in the least degree. Τῶ ἐν ῥ. would be utterly out of place; τοῦ ἐν ῥ. would be nonsense; but ἐν ῥ. as it stands by itself is just what is wanted as a characteristic explanation (like ἐν πνεύματι chap. 2:22, and many such cases). But τῶ ἐν ῥ. (if it be Greek, which is doubtful) would point to a specific agent that would make the bath. If the meaning were "purified by the bath of water by the word," the Greek would be διὰ τοῦ ῥ. or τῶ ῥ. But ἐν ῥ. is unequivocally the character of the thing spoken of as a whole. Τῶ λ. is the dative of the instrument; by the washing of the water they were purified: what was its character? It was ῥῆμα, or rather ἐν ῥ.
215 Again, this use of ἐν is quite common on all subjects. (Matt. 12:28; Luke 1:41, 77.). It characterizes. The reasoning on Ephesians 5:26 would connect the last case with δοῦναι, and turn the passage into folly. See Luke 4:32; 8:43; 21:23. It is simply to characterize the state. The article is no way needed, but rather its absence. So Romans 8:3; 12:8; 1 Corinthians 15:43. In fact it would be endless to cite cases of the sort. It is the regular characteristic style. Prepositions are Middleton's weak point. He followed Hellenism ably, but not the mental bearing of words. Nouns answer to "what?" as ὁ answers to "who" (or "which")? The article is indicative of an individual or individuals. Hence, prepositions or not, it makes no difference really. The absence of the article marks the nature or character of a thing; as here ἐν ῥήματι characterizes.
Compare John 15:3 for the doctrine. Both Ellicott and Alford are wrong in regarding sanctification as exclusively a progressive thing after initiation. It is so used, but even more frequently for the first setting apart to God. Here it appears to be used for the thing itself, and not distinctively either first or progressive. The apostle may allude to baptism (or, as is alleged, though very doubtful, to a sponsal bath); but he takes care to shew that it is the word that purifies, καθαρίσας ἐν τῶ λουτρῶ τοῦ ὕδατος ἐν ῥήματι being one sentence, which explains how the sanctification is effected. Christ, having loved the Church and given Himself for it, made it His, and does the other two things; He sanctifies it, and then presents it to Himself, being God as well as Second man. Its sanctification is by the purifying power of the word applied by the Holy Ghost.
Hence the "washing of water by [the] word" is right; and ἐν ῥ. characterizes the whole statement, being no more connected with καθαρίσας or ἁγ. than with τῶ λ. or τοῦ ὕδατος. It would not be ἐν ῥ. if it were specifically connected with either.