I still did not know that he was the one is the same phrase used in verse 31 (I did not know who he would be; Greek, “I did not know him”). John the Baptist is represented as repeating a statement and following it the second time with a more complete explanation. This interpretation is altogether in keeping with the style of the Fourth Gospel.

Although in Greek the article the does not appear before Holy Spirit, Anchor Bible (“a holy Spirit”) is the sole exception; Moffatt and Goodspeed render by “the holy Spirit.” By the use of a lower-case “h” in “holy,” these three translations attempt to capture the original meaning of John the Baptist’s words, apart from the influence of Christian theology. That is, they realize that John the Baptist would not be speaking of “the Holy Spirit” in the same sense that a Christian would understand the term. However, it is quite probable that John’s words should be understood in light of the theology of the Fourth Gospel, and so be translated the Holy Spirit. In light of all these considerations, the following conclusions seem valid: (1) To translate either “a holy Spirit” or “the holy Spirit” is problematical in view of the theology of the fourth evangelist. (2) The translation “the Holy Spirit” says more than the historical Baptist probably intended. (3) The neutral solution seems to be to render the expression as “God’s Spirit” (Die Bibel im heutigen Deutsch). What John is saying is that “the coming one” will inaugurate the age of God’s salvation when God’s Spirit will purify mankind. This meaning comes out clearly in the Gospels of Matthew and Luke, where “the coming one” baptizes not only with “God’s Spirit” but “with fire” (Matt 3.11; Luke 3.16). In those Gospels “the coming one” is looked upon not only as inaugurating the age of salvation but also as bringing God’s judgment on those who have rejected God’s authority.

In some languages serious problems are involved in translating baptizes with the Holy Spirit, because the expression for “baptize” contains within itself a reference to “water.” The meaning of this passage might then be understood as “initiates with water with the Holy Spirit.” When the basic term for “baptism” means essentially “to initiate into the faith,” it may be better to eliminate specific reference to water in this context and simply say “initiates by means of the Holy Spirit” or “purifies by giving God’s Spirit.” The function of the Holy Spirit may be spoken of as causative, and the final clause of verse 33 may be translated “he is the one who causes the Holy Spirit to initiate us into faith.”

Quoted with permission from Newman, Barclay M. and Nida, Eugene A. A Handbook on the Gospel of John. (UBS Handbook Series). New York: UBS, 1980. For this and other handbooks for translators see here .