{And I knew him not} (kag(9320)ouk (8869)dein auton). Repeated in
verse  33 . Second past perfect of oida as imperfect. He had
predicted the Messiah and described him before he met him and
baptized him. See the Synoptics for that story. Whether John knew
Jesus personally before the baptism we do not know. {But that he
should be made manifest to Israel} (all' hina phaner(9374)h(8869) t(9369)
Isra(886c)). Final clause with hina and first aorist passive
subjunctive of phanero(935c). The purpose of John's ministry was to
manifest to Israel with their spiritual privileges ( 1:49 ) the
presence of the Messiah. Hence he was baptizing in water those
who confessed their sins, he means, as in  Mr 1:5 . The Synoptic
account is presupposed all along here.