I have done some research, but I want a ‘pedagogical ‘ meaning, what is the message, the positive. Thank you.
A little more of the narrative for context:
31The Jews therefore, because it was the preparation, that the bodies should not remain upon the cross on the sabbath day, ( for that sabbath day was a high day,) besought Pilate that their legs might be broken, and that they might be taken away.
32Then came the soldiers, and broke the legs of the first, and of the other which was crucified with him. 33But when they came to Jesus, and saw that he was dead already, they broke not his legs: 34But one of the soldiers with a spear pierced his side, and forthwith came there out blood and water.
35And he that saw it bare record, and his record is true: and he knoweth that he saith true, that ye might believe. 36For these things were done, that the Scripture should be fulfilled, A bone of him shall not be broken. 37And again another Scripture saith, They shall look on him whom they pierced.
-- John 19:31-37 (KJV)
The Jews requested that Pilate expedite the death of those crucified by breaking their legs, but the soldiers recognised that Jesus was already dead, i.e. he lacked signs of life: breathing, movement of head or limbs. Specifically, he wasn't trying to support his weight by pushing against his feet to enable him to catch a breath, which is why the Jews wanted their legs broken -- to hasten death.1
One of the soldiers thrust a spear into Jesus' side. The reason for doing this was to further test whether Jesus was dead. If Jesus' body had still been alive it would have reacted in some way, but evidently there was no reaction from his body since the soldiers didn't bother to break his legs.
Verse 35 indicates that the record of this incident came from an eye-witness, one whose word John says could be trusted, "And he that saw it bare record, and his record is true: and he knoweth that he saith true, that ye might believe.". It seems pretty clear from this that the eye-witness was John himself, who bore witness to blood and water flowing from Jesus' side, which is indicative of a Pericardial Effusion.2,3
It would seem the trauma of the physical ordeal Jesus' endured (dehydration, beatings, journey to Golgotha, six hours on the cross), together with the mental and emotional anguish of caring for a dying nation who couldn't see their desperate need of his care (Matthew 23:37), brought about a heart attack that gave rise to the Percardial Effusion.
The only way to refute the "fact" of Jesus' death is to call the witness to this account, a liar. In other words, the soldiers didn't thrust a spear into Jesus' side to verify he was dead, and the witness concocted the detail of the "water and blood".
The writer of the book of Hebrews says:
For the word of God is quick, and powerful, and sharper than any two -edged sword, piercing even to the dividing asunder of soul and spirit, and of the joints and marrow, and is a discerner of the thoughts and intents of the heart.
-- Hebrews 4:12 (KJV)
So, theologically, the testimony of John in regard to the death of Jesus cannot help but move readers to declare their preference in regard to its truth. There will be those who prefer it to be true, and there will be those who prefer it not to be true. Each will gather evidence to support his/her preference. In this way, "the word of God ... is a discerner of the thoughts and intents of the heart."
There will be no guesswork involved in Jesus' decision concerning who will be saved. Those who want to be will step into the kingdom through the gate Jesus' has opened for them, and those who don't, won't.