• and he bowed his head and gave up his spirit.
31 • Since it was the day of Preparation,
and so that the bodies would 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.
Lest anyone should accuse the Jewish Authorities of euthanasia, they had a good religious excuse for bringing the crucifixion to an end in the onset of the Sabbath and a particularly cruel way of shortening the agony by breaking a prisoner's legs. Neither the crucifixion nor the leg-breaking were Jewish inventions of course and responsibility for the execution of Jesus ought always be seen as shared between all parties.
Cooperation between the Jewish council and the Roman procurator wasn't guaranteed of course so all the boxes on the form had to be ticked and the form rubber-stamped. It would have been no good just getting the execution over by leg-breaking to cause asphyxiation if the dead bodies had then been left to hang on their crosses until the Sabbath was over.
Asking for the crucifixion to be brought to an end and seeing it carried through was a perfectly normal use of a Friday, when they would always suspend some of their normal activities to prepare for the Sabbath. The Sabbath during the feast of Unleavened Bread required few if any extra preparations but just as a vigorous search would have taken place to make sure their houses had no yeast, no sight of this death should be allowed to leaven their Sabbath day.
This scheme to bring the dying of Christ to an untimely end was thwarted by his having died already. There would not be a tincture of doubt among the believers that men had brought his sacrifice of himself to an premature end. By giving up his spirit Jesus showed that the work was completed.
Truly, it is finished!