Not by works of righteousness which we have done, but according to his mercy he saved us, by washing of regeneration (διὰ λουτροῦ παλιγγενεσίας), and renewing of the Holy Ghost. (Titus 3:5)
Titus 3:5 is strong biblical evidence for the doctrine of baptismal regeneration. In his commentary on Titus, Jerome D. Quinn offered the following comments on this verse, particularly the phrase “by washing of regeneration” and how such teaches that water baptism, in the theology of the author, is the instrumental means God uses to regenerate people:
“saved us through a washing of regeneration and a renewal by the Holy Spirit.” Literally, “through a bath (dia loutrou) of regeneration (paliggenesias) and of renewal (anakainōseōs) of the Holy Spirit.” Before loutrou A reads the article, probably in order to harmonize this phrase with the preceding to eleos autou. A variety of Western witnesses (D*, F, G, L, b, d, g, Lcf., Ambst., etc.) read “through (dia) the Holy Spirit” (see 2 Tim 1:14), possibly under the influence of the preceding dia loutrou as well as dia Iesou Christou in the verse that follows. The reading would insure that the final terms of this chain of genitives would be read in an instrumental sense (see J.K. Elliot, Greek Text, p. 191).
“Through a washing”: The instrumental dia here is parallel in meaning to dia Iesou Christou in the next verse. For the dozen uses of dia in the Timothy correspondence, see 1 Tim 2:10, 15; 4:5, 14; 2: Tim 1:1, 6, 102, 14; 2:2; 3:15; 4:17. “Washing,” loutron, occurs otherwise in the NT only in Eph 5:26 of Christ “having cleansed [the church] by the washing (tōi loutrōi) of water with the word.” In the LXX loutron means the bath for cleansing sheep (LXX Cant 4:2; 6:6) and the Jewish ritual washing after touching the dead in Sir 34:25. The word does not appear in T. 12 Patr. Or the Ap. Frs., but Justin uses it in alluding to this passage in Titus or its source (Apology 1.61 [PG 6.420-21]; see Irenaeus, Adversus haereses 5.3 [PG 5.15.3]; Theophilus of Antioch, Ad Autolycum 2.16 [PG 6.1077]). (Jerome D. Quinn, The Letter to Titus: A New Translation and Commentary and An Introduction to Titus, I and II Timothy, the Pastoral Epistles [AB 35; New York: Doubleday, 1990], 194)
If there was a baptismal hymn behind [Titus 3:4-7] (and the resemblances to 1 Pet have suggested the hypothesis), it has been freely reshaped in the tradition, probably the liturgical tradition for baptism, to form a prose, didactic prayer (an oratio, as the Roman rite called such compositions in Latin liturgy). The author of Titus cited the rolling cadences of a single sentence from that prayer, which in turn may have taken up and amplified a prior hymnic confession by the church assembled for baptism (the schema that remains to this day in the Easter Eve baptismal eucharist in the Roman rite is Scripture reading, hymnic response, oration). The insertion of another pistos logos into the center of the great thanksgiving prayer of 1 Tim 1:12-17 may be modelled on the prayer context suggested for this passage in Titus. G. Cuming (“EYCHēS, p. 81, discussing an elusive phrase in Justin, Apology 1.66.2) has proposed that logos in that phrase means “a form/patter of words” proper to a particular prayer of thanksgiving (see 1.13.1). A Gelston (“Euchēs,” pp. 172-175) has reservations about other aspects of Cuming’s evidence, but a prayer formula cited here in Titus would support Cuming’s case. In any case, the practices of ancient formal rhetoric adequately account for the form of the citation in Tutus without recourse to a much more problematic poetic source (see Lash, “Hymn-Hunting,” pp. 293-297, with its reference to Marrou, Education, p. 197). (Ibid., 211, comment in square bracket added for clarification)
More basis for the P[astoral]E[pistles] is the verb sōizein. A baptismal paraenesis later in Titus contains the only use of this verb in the letter. It describes how “our savior, God . . . saved us, no thanks to any upright deeds that we performed ourselves but because of (kata) his own mercy, saved us through a washing of regeneration and of renewal by the Holy Spirit that he poured our lavishly on us, through (dia) Jesus Christ, our savior. God’s was the grace (tei ekeinou charity) that made us upright (Titus 3:4-7). For the PE the action of saving is ultimately an act of God as ho theos, the Father (c. 1 Tim 2:3-4 with 2 Tim 1:8-9). Precisely because of the relationship in which Jesus stands to the Father, he too can be the subject of sōizein (1 Tim 1:15; 2 Tim 4:18). (Ibid. 305, comments in square brackets added for clarification)