BY William-Hayward
Good question!
The answer is MAYBE ... so hang on, this is a bit complex.
John the Baptist is the son of Elizabeth, who is a relative of Mary, the mother of Jesus (Luke 1:36). Probably, they were cousins, meaning John the Baptist and Jesus were 2nd cousins. Now, on to John the apostle.
In Matthew 27:56 it’s said that “Mary Magdalene, and Mary the mother of James and Joseph, and the mother of the sons of Zebedee” were (among) the women looking at Jesus on the cross.
Compare this to the passage in John 19:25, where it states the women at the cross is “His [Jesus] mother, and His mother’s sister, Mary [the wife] of Clopas, and Mary Magdalene.”
“Mary [the wife] of Clopas” is most likely “Mary the mother of James Joseph”.
However, what are we to make of “His mother’s sister”? The text is fairly ambiguous, it could mean;
(1) that Mary of Clopas is the sister of Mary the mother of Jesus, or
(2) that there’s another women who is Jesus’ aunt.
f we are to take option (2) as true, then it’s entirely plausible that this aunt of Jesus, is actually the same as the “mother of the sons of Zebedee” (her name is Salome, compare Mark 15:40 Matt 27:56).
IF THIS IS THE CASE, then the apostle John is Jesus’ cousin. So, since John the Baptist is Jesus’ 2nd cousin, and John the apostle is Jesus’ cousin, it logically follows that John the Baptist & John the apostle ARE related — provided that both are from Mary’s side of the family.
However, that’s only a POSSIBILITY.
;We also have to consider option (1) - that Mary of Clopas is Jesus’ aunt. As it would be, this conclusion seems to be slightly more probable, which would mean the two Johns are not related.
One might object that that Mary would not have a sister also named Mary. That would be a solid criticism, were it so simple, but that’s where the external evidence comes in. Hegesippus, writing AD 165–175, testifies that Clopas was the brother of Joseph (Jesus’ step-father), meaning Mary of Clopas is the wife of Joseph’s brother, which in turn means that “His mother’s sister” as John stated, is actually a simplified/compressed version of “His mother’s husband’s brother’s wife” i.e. “Mary’s brother-in-law’s wife”.
So, to summarise: Despite the possibility of John and John being related (2nd cousins), I'm inclined to believe they are not. But due to the antiquity’s ever-so-often fragmented nature, possible confusion of names, and spoonful speculation, one cannot be too dogmatic either way.
Thank you for reading thus far, hope it was informative.