The breaking of the legs

In John 19 (31-36) we read: "The Jews therefore, because it was the preparation, 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. Then came the soldiers, and brake the legs of the first, and of the other which was crucified with him. But when they came to Jesus, and saw that he was dead already, they brake not his legs: But one of the soldiers with a spear pierced his side, and forthwith came there out blood and water. And he that saw it bare record, and his record is true: and he knoweth that he saith true, that ye might believe. For these things were done, that the scripture should be fulfilled, A bone of him shall not be broken."

The reference is to Psalm 34.20 & Exodus 12.46. We're explicitly told that the Jews (presumably, the temple authorities) asked that the bones be broken. They would have known the prophecy, and by encouraging the breaking of the bones, would know that a break would vitiate the fulfillment in Christ. Given the hostility of the temple authorities, I wonder if this was behind the request to Pilate.