John 19:31

The Jews therefore (because it was the preparation) that the bodies should not remain on the cross on the sabbath day (for that sabbath-day was an high day) besought Pilate that their legs might be broken, and that they might be taken away. See Deut. xxi. 22. This was done, in order that they might not pollute and make gloomy this most solemn festival, by the horror of their sufferings, as St. Augustine says. It was necessary therefore that they should die and be buried before sunset, at which time the sabbath began. "That," as Theophylact says, "the sun might not set on their sufferings."

For this was the sabbath within the octave of the Passover, and for this reason a more solemn day than other sabbaths.

Their legs were to be broken with the strong blows of a mallet or iron bar, to make them die the sooner, from the intensity of the pain, or the loss of blood, or because the vital force resides in the knees and legs. (See Pliny, N. H. xi. 45.)

But why did they not pierce their hearts with a spear or sword, which would have been an easier and a quicker death? They preferred to break the legs of criminals, in order to increase their sufferings, as even now notorious criminals are put on the rack. Probably the Jews wished to do this to Christ, out of bitter hatred, and Baronius thinks that they gave Him vinegar to keep Him alive for this further torture. But He was already dead, not because He dreaded this further suffering, but on account of the mystery (of which more presently), but also because His strength was worn out by all He had already undergone. (See Lipsius, de Cruce, ii. 14.)

These Jews seemed to urge their being taken down from the cross, not so much from any regard for the sabbath, as from dread, shame, and consciousness of guilt. For they saw the sun darkened, the veil of the temple rent, the earthquake, &c., all which condemned their treatment of Christ. And they therefore feared either that God would punish them, or the people rise up against them as the murderers of Christ. They ordered Him therefore to be taken down from His seat of triumph, and to be buried. See F. Lucas. Ver. 33. But when they came to Jesus (evidently to break His legs. Euthymius says, "They came to Him last, as wishing to please the Jews by treating Him with greater insult) and saw that He was dead already, they brake not His legs. He did not wish His legs to be broken, for He wished to rise again with an unmutilated body." As Lactantius says (iv. 26), "His body is taken down from the cross entire, and carefully laid in the tomb, lest by the loss of any limb it might be rendered less seemly for resurrection."

Instead, then, of His legs being broken, His side was pierced with the spear. This was after He was dead, not while He was alive as some have thought. This error was condemned in the Council of Vienne. For as Christ, while alive, gave up His whole Body for us, so did He in His death wish to give us His heart. For this it was that was pierced by the spear, and blood and water flowed forth from it, so that He gave Himself entirely to us.

You will say that Christ was already dead, and that therefore He merited nothing by this piercing of His heart. But I reply that when alive He knew this wound would be inflicted, and that He offered it to the Father for us, and thus merited and effected our salvation. Thou wilt say next, We see that blood flows from the body of a slain person, if the murderer is present. This then is a natural effect. I say that it is not natural, but very nearly miraculous; to point out and confound the murderer. And much more was it miraculous in the case of Christ, as I will presently show.