John 19:31

“The Jews, therefore, since it was the preparation,” i.e., Friday, the day before the Sabbath, “and as the day of that Sabbath was great,” being not only an ordinary Sabbath but the Passover, “that the bodies might not hang on the cross on the Sabbath” and so defile it, “they asked Pilate that their legs might be broken, and that they might be removed”. The law of Deuteronomy 21:23 was that the body of a criminal should “not remain all night upon the tree”. This law seems not to have been in view; but rather the fear of polluting their great feast. The Roman custom was to leave the body to birds and beasts of prey. To secure speedy death the crurifragium, breaking of the legs with a heavy mallet or bar, was sometimes resorted to: as without such means the crucified might in some cases linger for thirty-six hours. Neander (Life of Christ, p. 473) has an interesting note on crurifragium; and cf. the Gospel according to Peter on σκελοκοπία, with the note by the Author of Supernat. Religion.