Answer: After Jesus was already dead, one of the soldiers pierced Jesus' side with a spear, bringing a sudden flow of blood and water, (verses 33 and 34).
MORE INFORMATION AND/OR OTHER SCRIPTURE REFERENCES:
NOTE: The blood and water were the result of the spear piercing the sac that surrounds the heart (called the "pericardium") and the heart itself. This was probably done to make sure that Jesus really was dead, but it could have simply been a brutal action on the part of the soldier.
It was extremely unusual for a victim of crucifixion not to have broken legs. The breaking of the legs caused the one being crucified to be unable to push his body upward (pushing his feet against the spike driven through his feet) and thus be able to take air into his lungs. It hastened death. It was also unusual for a spear thrust (done with enough force to pierce through several inches of flesh, muscle and internal organs) NOT to break bones in the rib cage area. But in our Passover Lamb--the Lamb of God--no bones were broken, and the Scriptures were fulfilled:
Exodus 12:46: "It [the Passover lamb] must be eaten inside one house; take none of the meat outside the house. Do not break any of the bones."
Numbers 9:11-12: "They are to celebrate it [the Lord's Passover] on the fourteenth day of the second month at twilight. They are to eat the lamb, together with unleavened bread and bitter herbs. They must not leave any of it till morning or break any of its bones. When they celebrate the Passover, they must follow all the regulations."
Psalm 34:20: "He protects all His bones, not one of them will be broken."
"The One they have pierced":
Zechariah 12:10: "And I will pour out on the house of David and the inhabitants of Jerusalem a spirit of grace and supplication. They will look on Me, the One they have pierced, and they will mourn for Him as one mourns for an only child, and grieve bitterly for Him as one grieves for a firstborn son."
Revelation 1:7: "Look, He is coming with the clouds, and every eye will see Him, even those who pierced Him; and all the peoples of the earth will mourn because of Him. So shall it be! Amen."
By water and the blood:
1 John 5:6-8: "This is the One Who came by water and blood--Jesus Christ. He did not come by water only, but by water and blood. And it is the Spirit Who testifies, because the Spirit is the Truth. For there are three that testify: the Spirit, the water and the blood; and the three are in agreement."
