Therefore, because it was the Preparation Day, that the bodies should not remain on the cross on the Sabbath (for that Sabbath was a high day), the Jews asked Pilate that their legs might be broken, and that they might be taken away. 32 Then the soldiers came and broke the legs of the first and of the other who was crucified with Him. 33 But when they came to Jesus and saw that He was already dead, they did not break His legs. 34 But one of the soldiers pierced His side with a spear, and immediately blood and water came out. 35 And he who has seen has testified, and his testimony is true; and he knows that he is telling the truth, so that you may believe. 36 For these things were done that the Scripture should be fulfilled, “Not one of His bones shall be broken.” 37 And again another Scripture says, “They shall look on Him whom they pierced.” — John 19:31-37.
John testifies to faithful eye-witnessing of what happens. To hasten death by suffocation, caused by increased pressure on the lungs, the legs of the crucified thieves are broken. Jesus, however, is already dead, and a soldier’s spear pierces His side, resulting in the outflow of blood and water. (This is held by some medical doctors to be a description of the separation of blood and serum through the piercing by the spear of the pericardial sack after acute heart failure.) The death of Jesus is well attested. The Bible is also faithfully fulfilled in that none of His bones are broken [Exodus 12:46; Numbers 9:12; Psalm 34:20] and those who pierced Him look on Him [Zechariah 12:10]. [Source: Bible Panorama.]