The Gospel of John records the words of John the Baptizer, that he “did not know” Jesus when the latter went to him to be baptized in the Jordan: “I myself did not know him, but the reason I came baptizing with water was that he might be revealed to Israel … I saw the Spirit come down from heaven as a dove and remain on him. And I myself did not know him, but the one who sent me to baptize with water told me, ‘The man on whom you see the Spirit come down and remain is the one who will baptize with the Holy Spirit’” (John 1:31-33).
But, as many skeptics have pointed out, John was a relative of Jesus. John’s mother Elizabeth knew Jesus’ mother Mary, and knew that she was to be the mother of the Messiah (Luke 1:43), and it is unlikely that John would never have met Jesus and did not know him. Furthermore, Matthew records that as John spoke to the Jews well before the baptism of Jesus he told them: “… after me comes one who is more powerful than I, whose sandals I am not worthy to carry” (Matthew 3:11). When Jesus did go to John for baptism, but before John saw the Spirit descend on him, John objected that he was, indeed, unworthy to perform the immersion for Jesus (Matthew 3:14), indicating that he not only knew Jesus, but also knew who he probably was.
The solution to this apparent contradiction between Matthew and John is that the Greek language in which the New Testament was written has several words which may be used for “knowing.” The word oida – which was used by the Baptizer to say he did not “know” Jesus (and also that the Jews did not “know” Jesus in John 1:26) – carries the meaning of what we might call firm or certain knowledge – to know “for sure,” as we might say. It would seem that although John probably knew Jesus from childhood and was aware of many of the signs indicating he might be the promised Messiah, he did not know “for sure” that Jesus was, indeed, the Christ until he saw “the Spirit come down from heaven as a dove and remain on him” (John 1:32).