John Calvin Commentary John 19:33

"but when they came to Jesus, and saw that he was dead already, they brake not his legs:" — John 19:33 (ASV)

But when they came to Jesus, and saw that he was already dead. That they break the legs of the two robbers, and after having done so, find that Christ is already dead, and therefore do not touch his body, appears to be a very extraordinary work of God's providence.

Ungodly men will, no doubt, say that it happens naturally that one man dies sooner than another; but, if we examine carefully the whole course of the narrative, we will be constrained to ascribe it to the secret purpose of God, that the death of Christ was brought on much more rapidly than men could have at all expected, and that this prevented his legs from being broken.