Matthew 27:24-26
And all the people answered, “His blood be on us and on our children!” (Matthew 27:25 ESV)
Pilate washed his hands as a symbolic gesture. A sign that he had given Jesus over to the mob, but did not recognize or understand their desire to see him crucified. He wanted no blame.
The mob took the blame. They knew according to their laws and traditions that they would be held responsible for Jesus' death. They accepted the notion that his blood would be on them—without even understanding that that was the whole point.
Jesus' blood was the permanent replacement for the Old Covenant's sacrifices. It is through the spilled blood of Christ that our sins are forgiven. It is the faithful acceptance of his work that salvation takes place. Yes, God, please let his blood be on us and on our children.