Have you ever wondered why, given the detail in God's Word, God never saw fit to include penal substitution in the actual text of Scripture but instead left it hidden for almost 2000 years awaiting the Reformation?
"But he was wounded for our transgressions, he was bruised for our iniquities: the chastisement of our peace was upon him; and with his stripes we are healed."
Isaiah like Daniel never even mentioned the Cross, but Jesus being cut off.
Isaiah claims it was the stripes or beating Jesus received that healed us.
"Yet it pleased the Lord to bruise him; he hath put him to grief: when thou shalt make his soul an offering for sin, he shall see his seed, he shall prolong his days, and the pleasure of the Lord shall prosper in his hand. He shall see of the travail of his soul, and shall be satisfied: by his knowledge shall my righteous servant justify many; for he shall bear their iniquities."
That process started in the Garden when Jesus started to sweat drops of blood.
The point of suffering was already placed on Jesus prior to the form of death, via a Roman Cross. Even Paul pointed out it was cursed to hang on a tree, not that the Cross was the substitute way to die.
The Cross was for that generation to realize how far they would go to cut off their own Messiah in total rejection.
To simply die and be cut off would have worked to fulfill the OT Scriptures. Now one can argue that Moses lifted up the serpent on a stake, but that was used by Jesus explaining to Nicodemus something new and different from the OT.
The argument could be made that only Adam needed to be punished for disobedience, as only by his disobedience, death happened. Had things worked out according to human theory, only Adam would need to be redeemed. Because no one seems to acknowledge that Adam physically died that day. They theorize with Satan, that Adam would not die, but in a "state of death" would eventually physically die. That is Satan deception on the church, and not sure when that deception took hold.
Adam and Eve did physically die that day. God took away their permanent incorruptible physical body, and gave them a body of death, that was corruptible with decay. So all were born after Noah into death, and were already dead. What Jesus finished was the power of that death, by physically dying, and bringing His body back to life again. And it was a Cross, because Jesus told Nicodemus it would be a Cross.
So the Lamb had already suffered the penalty of sin, even before the Cross. Being slain fulfilled the cut off part. Jesus then experienced death as all who have lived death. And that moment was when death was broken for all the OT redeemed. They experienced the resurrection of life from that moment on.
From that moment, it was finished, those redeemed in Christ would never taste death, nor would physical death be a death ending. The only state of death would be this current physical body they were born with.
It was not that a lamb had to die under the Law. It was that the sin of that person was transferred prior to death. So death was not transferred, the sin was transferred. The substitution was not in the death, because the sinner was already dead. The substitution was that the lamb took on that sin prior to death. Then the lamb had to die. Jesus had to experience death, but had already been the substitution for the sin.
From both the OT point and the NT point one can justify a separation from the Cross and the actual fulfillment of taking on the sin of the world. But most forget about the judgment prior to the Cross, and see the Cross as the only point of sin being carried.
Jesus also had to be cut off, as that is the only way God would also experience death itself. But the Cross was not the point of substitution. Humans are already dead, they don't have to die because of sin. That is what most do not take under consideration. The OT redeemed were made alive even before Jesus rose from the dead, ie was made alive.
That is why Matthew 27:52-53 sounds strange to us.
"And the graves were opened; and many bodies of the saints which slept arose, And came out of the graves after his resurrection, and went into the holy city, and appeared unto many."
The graves were opened and bodies came out at that moment. They permanently were out of death, as they ascended to heaven on Sunday morning when Jesus ascended, and presented them as the firstfruits of being made alive. They would never return to the grave.
The point is that Jesus could have "just died" without the drama of the Cross, and His own people forcing the Romans to crucify an innocent man, even though Jesus did carry the sins of the world at that moment. To the Romans He was innocent. Even though Jesus carried all their sins as well. The Cross was the downfall of Jesus' own people. As they cried that His blood be on their hands and their children's hands.
My point is that the Cross was not the penal substitution. The judgment of stripes and beating prior to the Cross was the penal substitution. That was when sin was transferred onto Christ.
The serpent in the wilderness was not part of the understood perfect lamb substitution, nor a type. So the Cross was not a typical type of an alter, but an extra curse for His own people and their soon desolation.