Or: ignorance of physiology can lead to misinterpretation of the New Testament.
John’s gospel has the following in the description of the crucifixion (John 19:31-35):1
Therefore, the Jews asked Pilate in-order-that the bodies should not remain upon the cross on the Sabbath since it was the Preparation (for the day of that Sabbath was a great day), that their legs might be fractured and that they might be taken down.
Therefore, the soldiers came, and indeed fractured the legs of the first and of the other one who was crucified together-with him, but after they came upon Jesus, as they saw him the one who had already died, they did not fracture his legs; but one of the soldiers pierced his rib-cage with a spear and immediately blood and water came forth.
And he who has seen, has testified and his testimony is true and he knows that he says true things, in-order-that you might believe.
But — is this testimony true? I mean, did an eye-witness see blood and water come forth from the rib-cage of the dead Jesus?
One approach is physiological — it is to ask whether it is plausible that something like this would happen if cutting into the chest of a crucified man after death. It appears that the answer to this is Yes — severe flogging followed by crucifixion may lead to the build-up of effusions (fluid) in the linings of the heart and lungs. This in turn will appear as clear water-like fluid when someone cuts into the chest. See Edwards et al 1986 (On the Physical Death of Jesus Christ. Journal of the American Medical Association) for a discussion.2
Therefore, the water probably represented serous pleural and pericardial fluid, and would have preceded the flow of blood and been smaller in volume than the blood. Perhaps in the setting of hypovolemia and impending acute heart failure, pleural and pericardial effusions may have developed and would have added to the volume of apparent water.
So one model of the Gospel text would be that it is a direct or relayed account by an eye-witness who did indeed see blood and something like water, was surprised by it, thought it might be important, and so wrote it down, or told someone else, who wrote it down. And of course that person might also have come to think that this event had some deeper meaning, as the death of Jesus itself had a deeper meaning than the surface description, of another judicial execution. That is, the event happened, and looking back, the event can be seen as having deeper meaning.
Another model is that no-one saw this, and it did not happen, but someone thought we should believe it, in some sense, for the sake of a deeper meaning.
For example, Rudolf Bultmann had a complicated3 and now largely rejected4 theory of John’s Gospel where someone (the “ecclesiastical redactor”) assembled and edited and added to material from three different, now-lost written sources to form the current Gospel. The redactor “was anxious to make the Gospel more acceptable to the church by introducing doctrinal references…”5
Bultmann was confident that the “blood and water” event was a later and symbolic addition by the “ecclesiastical redactor”:
The ecclesiastical redaction has gained yet another and deeper meaning from the lance-thrust, in that it adds in v. 34b, καὶ ἐξῆλθεν εὐθὺς αἷμα καὶ ὕδωρ [and immediately there came out blood and water]. Doubtless a miracle is being recounted here, and equally doubtless this miracle has a definite meaning. It can scarcely be other than that in the death of Jesus on the cross the sacraments of baptism and the Lord’s Supper have their foundation.6
It seems to me that part of his argument is that — because the event can be seen to have symbolic meaning — it is likely it was invented.
Of course, we don’t know whether Bultmann would have written differently if he was aware that it was quite plausible that an eye-witness to the soldier’s spear would have seen something like blood and water spill from the wound.
New Testament quotations are from the Modern Literal Version, 2026 Beta Update, unless otherwise noted.↩︎
William D Edwards, Wesley J. Gabel, Floyd E. Hosmer On the Physical Death of Jesus Christ. JAMA. 1986;255(11):1455–1463. doi:10.1001/jama.1986.03370110077025. JAMA-link↩︎
Smalley, Stephen S. (1978) John, evangelist and interpreter, Paternoster Press, Exeter archive.org link — page 105.↩︎
For example — from The Signs Gospel, Wikipedia: “After the commentary of Rudolf Bultmann was published in 1941, the hypothesis of a semeia (sign or miracle) source was supported by those who favor Johannine independence from the synoptic Gospels, but scholars today agree that the existence of a single signs source for the miracles in John is highly unlikely.”. See also Wikipedia on Form Criticism — a primary technique used by Bultmann.↩︎
Smalley, Stephen S. (1978) John, evangelist and interpreter, Paternoster Press, Exeter archive.org link — page 105.↩︎
Rudolf Bultmann (1971) The Gospel of John: a commentary, translated by Beasley-Murray, Hoare and Riches archive.org link — pages 677-678↩︎