One hears from time to time suggestions that the Jews retort to the Lord in John 8.41, "We be not born of fornication", was in fact a slanted suggestion that the legitimacy of His birth was in question. The implication of this suggestion was that the pure virgin from Nazareth, Mary his mother, was guilty of fornication. Not only is such a suggestion repugnant as a thought applied to our beloved Lord Jesus it is purely speculative and unworthy of public expression.
What so incensed the Jews was Christs word in that verse, "Ye do the deeds of your father", with its inference that they were spiritual fornicators or idolaters. To which they immediately retorted, "We be not born of fornication", meaning themselves nationally, and it was in no sense an innuendo that Christ was the object of their statement. That this is the correct interpretation is proved by their following assertion, " we have one Father, even God". They were claiming a divine fatherhood and strongly refuting any allegation that they were spiritual fornicators. They had a proven historical relationship to the God of Israel through Abraham, the father of the nation according to the flesh, who said, "Thus saith the Lord, Israel is my son, even my firstborn" (Ex 4.22). To them belonged "the adoption" (Rom 9.4), the God of Abraham, Isaac, and Jacob was their God; they were true blood-line sons of Israel and in no sense would tolerate the Lords word that they had another "father", the Devil (v.44).
Further, their immediate reaction was based upon their understanding that the Lord was referring to spiritual fornication; it was a reflection of Old Testament symbolism, with which they were totally familiar, likening idolatry to spiritual fornication. This is borne out by passages such as Hosea 2.1-8, and especially v.4 where Israel is compared to "children of whoredoms". Also, the reason why Hosea needed to take "a wife of whoredoms" (1.2) was because "the land hath committed great whoredom, departing from the Lord". It is this spiritual "fornication" which the Jews were denying. There is far more contextual credibility in this exegesis of the passage than ever there is in the unsupported assumption they were taunting Christ with His supposed illegitimate birth. There is not one whit of evidence to support such an offensive construction.
There are further clear reasons, apart from this single isolated text, why these Jews were not thinking of our Lords suspect parentage when they spoke as they did. It is because they had not the slightest suspicion that Jesus was anything other than the son of Joseph and Mary, and brother to his Nazareth home siblings. This is proved by several texts dealing with "the Jews" and what they said. "And they said, Is not this Jesus, the son of Joseph, whose father and mother we know? how is it then that he saith, I came down from heaven?" (Jn 6.42). They were quite sure they "knew" Jesus and who his parents were, and that this was an indisputable fact needing no argument! Again, look at John 7.27: "Howbeit we know this man whence he is: but when Christ cometh, no man knoweth whence he is".
In that same chapter (vv.40-43) when disputing whether Jesus was or was not the looked for Messiah, the argument of the common people pivoted on the known Scriptural fact that Messiah would not come out of Galilee, where they obviously believed Jesus was from. They knew nothing whatsoever about Marys Holy Spirit conception, Bethlehem, and Jesus birth there as vv.41-42 makes clear. Further, v.52 is just as clear that neither did the religious hierarchy, the chief priests and Pharisees, know anything about Bethlehem and Jesus birth in the city of David, or the events of Matthew 1! So, having no knowledge of Bethlehem, they all assumed he was born in Galilee. Thus the speculation some see in the Jews reply at John 8.41 that Jesus was born of fornication is unfounded, distasteful, and unbecoming.
The passage in Mark 6.3-6 is similar proof that the local people who knew Him as "the carpenter" never had any such accusations either. To them He was "the son of Mary" (Joseph was probably dead at this time, as he is not mentioned, and Mary a widow), brother to James, Joses, Juda, and Simon, and His sisters were known too! Then the identities of the people who knew Him so well (or thought they did!) are spelled out by the Lord as being those of His own country (i.e. Nazareth), His own kin, and in His own house (v.4)! Even those who were so close to Him did not know or understand the secret mystery of His birth, so if they did not know, it is abundantly evident the mystery of the virgin birth and the annunciation by the angel Gabriel to Mary, and Josephs dream, was also not generally known, and could not therefore have been misunderstood and turned into an accusation that He was "born of fornication"!
The incident in Matthew 1.18-19 is clear evidence that the pregnancy of Mary was not a "public" scandal, and in order to keep it that way Joseph, until Gabriel revealed to him the miraculous conception in a dream, was minded to quietly hide her away somewhere. Apart from Joseph, who would have known anyway? The text does not mention any other who might have been aware, and the Angel appeared only to him very privately in a dream. Then what was by the Spirit known to Elisabeth and Zacharias, the parents of John the Baptist, was revealed to those who were in the intimate family circle, and like the shepherds, and Simeon and Anna, very localised in the general Jerusalem area. Annas report to the small Messianic group in Jerusalem was likewise restricted locally (Lk 2.38). Mary evidently told no one, not even her other children seemingly (Jn 7.5), but pondered all the events and sayings relating to her Messiah Son, "in her heart" (Lk 2.19,51). So the inhabitants of Nazareth knew nothing whatsoever about the matter, seeing only that Joseph had taken Mary, and was living with her as his wife (Mt 1.24). It certainly was not known to them that Joseph, "knew her not till she had brought forth her firstborn son". Thus her condition would have seemed perfectly natural to them. This non-reaction, and so lack of gossip locally, when it became evident Mary had conceived, and the recorded statements of the local Nazarenes when Jesus was grown to manhood, confirm this. The events surrounding Jesus conception in this very ordinary artisan family would have had no wider significance beyond the family home in Nazareth, and had faded with time and had providentially been lost to memory. Thus we find no credible grounds for viewing John 8.41 as a personal accusation levelled at the Lord.