THE CROSS.

What was the meaning of the cross and the death of Jesus on it?
The death of Jesus fulfilled the Old Covenant and created a New Covenant. Hebrews chapters 9 to 10. The Old Covenant was based upon the blood of animal sacrifices, but the New Covenant involved the blood of the perfect Son of God. This new Covenant could take away the sin and make a persons heart clean, there is no animal sacrifice which would be able to do this.

History.

The cross was originally just a pointed post hammered into the ground. It may have originally been part of the fortification or the protection around a city.
The person was tied to the post in preparation for torture or punishment. The person usually being made to hang from his arms during the punishment.
Later a cross-piece (patibulum) was added to the upper part of the post, to which a person could be tied or nailed.
This practice was often used by the Semiramis and Phoenician during the 6th and 5th centuries.
Many nations have adopted this method of punishment, including the Romans. It was finally abolished in the Roman Empire by Constantine in 315 AD.

The Jews use of hanging or crucifixion of a person appears to have been carried out only for the purposes of punishment for those guilty of idolatry and blasphemy.

Terrible leaders such as Antiochus Epiphanes crucified those who refused to turn away from the old Jewish religion, and the Maccabean king Alexander Jannaeus used crucifixion after an insurrection in 88 B.C..
In 4 B.C. the Roman general called Varus is reported to have crucified 2,000 people during the siege of Jerusalem by Titus (AD 70). So many were crucified that they ran out of both wood and places to put the crosses.

There have been a number of designs for crosses over the ages. The fact that there was a superscription fitted to the top of the cross above the head of Jesus Matt 27:37; Luke 23:38 indicates that the cross of Jesus was the traditional shape.

The action of Crucifixion took place normally outside of the city and the person about to die would be expected to normally carry his cross to the place of execution, probably just the patibulum, the horizontal piece to which his hands would be eventually nailed. The upright was normally permanently fixed already in the ground.
It seems most likely that the hands were nailed to the horizontal piece while laid upon the ground, and then the horizontal piece of wood, with the person nailed to it, was drawn up by ropes and attached to the upright. The feet were then nailed to the upright. The fact that Jesus spoke with the people by the cross and was also offered a sponge on a hyssop-stalk. John 19:29, indicates that His feet were only a foot or so above the ground.

Death by this method usually took quite a long time, often as long as thirty-six hours, and it is recorded to have taking as long as nine days at least once.
The centurion and four soldiers would have been as a guard to prevent any rescue attempt. Matt 27 54;

"Now when the centurion, and they that were with him, watching Jesus, saw the earthquake, and those things that were done, they feared greatly, saying, Truly this was the Son of God."

John 19:23.

"Then the soldiers, when they had crucified Jesus, took his garments, and made four parts, to every soldier a part; and also his coat: now the coat was without seam, woven from the top throughout. "

The pain was obviously agonizing, as the nailed hands and feet took the weight of the body. Breathing could have been difficult because the arms were held out sideways, this required the person to push down on the feet to be able to take a breath.
Obviously the hands and feet would be bleeding and the body would be losing blood rapidly, the loss of blood pressure would cause a throbbing headache. Eventually a fever and possible the infection of tetanus would set in. Death was normally by loss of blood, infection and exposure to the sun etc.

When, for any reason, it was necessary to put the sufferer out of their misery before their death, the person being crucified would have their legs broken with a club or hammer, this meant that it became very difficult to breath and they would quickly died of asphyxiation.
John 19:31-37

"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.
And again another scripture saith, They shall look on him whom they pierced."

To make sure that Jesus was dead a soldier pushed a spear into His side. This action would often have taken place just to make sure the person on the cross was dead. The "blood and water" would be an indication that the person had been dead for some time. This is the proof that there was no way that Jesus could have come back to life naturally.