1 After that the Lord Jesus had accomplished all that He foreknew required accomplishment before His death, and had, when it pleased Himself, given up the ghost, what followed thereafter, as related by the evangelist, let us now consider. “The Jews therefore,” he says, “because it was the preparation (parasceve), that the bodies should not remain upon 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.” Not that their legs might be taken away, but the persons themselves whose legs were broken for the purpose of effecting their death, and permitting them to be detached from the tree, lest their continuing to hang on the crosses should defile the great festal day by the horrible spectacle of their day-long torments.
Source: Tractates on the Gospel of John (New Advent)