They will look on the one whom they have pierced; They will mourn for him as for an only son, And weep for him as people weep for a first-born child. [Zech 12:10]

Saint John uses part of this text of Zechariah to comment on the fact that, to ensure Jesus' death, the Roman soldier did not break his legs but rather pierced his side: "They will look on the one whom they have pierced." (Jn 19:37).

Reading these lines as Hebrew poetry reveals to us that "The one whom they pierced", "only Son" and "first-born child" are parallel and speak of the same person. In the fulfilment of the prophecy, that person is the crucified Jesus, the only Son of God, Mary's "first born" and her only child. A discussion of the technical term "first-born" would only be a distraction here. It is enough to note that only in the case of Jesus does "first born" refer to the child's relationship with the mother instead of the father. Thus, John's use of Zechariah's text makes a wonderful contribution to our understanding of both Jesus and Mary's absolutely unique relation with her only Son.