Bible passage: Exodus 12:46
Written: As early as 1400 BC
In Exodus 12, Moses is giving out the rules for the preparation and handling of lambs for the first Passover. Among the rules, the bones of the lambs should not be broken:
46 "It must be eaten inside the house; take none of the meat outside the house. Do not break any of the bones." (Exodus 12:46, NIV)
The lamb also had to be blemish free (Exodus 12:5) and adhere to other criteria that are explained in Exodus 12.
After the time of Moses, about 3,400 years ago, up until the time of the Roman destruction of Jerusalem, about 2,000 years ago, lambs were sacrificed each year to help commemorate God's deliverance of the Israelites during the Exodus.
About 2,000 years ago, Jesus, the Messiah who had been promised by the prophets of the Old Testament, became the ultimate Passover lamb, when he was crucified by the Romans.
That is why some New Testament writers refer to Jesus as a sacrificial lamb, or even specifically as the Passover lamb, such as Paul, the author of 1 Corinthians 5:7.
To be consistent with the rules for a Passover lamb, it would be important that none of Jesus' bones would be broken during his crucifixion and death.
Crucifixions were common during Roman times. The people who were crucified could suffer for days before dying. One way to speed up the process of death was to break the legs of those who were crucified. Once their legs were broken, they could not use them to support their body weight, which made breathing more difficult, and they then would die more quickly.
This is what John describes as happening to two of the men who were crucified at the same time as Jesus. But John also writes that the legs of Jesus were not broken:
31 Now it was the day of Preparation, and the next day was to be a special Sabbath. Because the Jewish leaders did not want the bodies left on the crosses during the Sabbath, they asked Pilate to have the legs broken and the bodies taken down. 32 The soldiers therefore came and broke the legs of the first man who had been crucified with Jesus, and then those of the other. 33 But when they came to Jesus and found that he was already dead, they did not break his legs. 34 Instead, one of the soldiers pierced Jesus' side with a spear, bringing a sudden flow of blood and water. (John 19:31-34, NIV)