When one has the attention of another, it is effective to repeat and summarize the thoughts previously expressed. The writer of the Hebrews letter used that tool as he was preparing to address other matters to his readers. He repeated that the Law of Moses was only a shadow or symbol of the new law which Christ had established through His death. It did not render the forgiveness of sins.
The writer stated that it is not possible for the blood of bulls and goats to take away sins. If it had been possible, there would have been no need for the daily offerings of the priests and the yearly sacrifices on the Day of Atonement. Christ did make full forgiveness possible once for all. He took away the first testament and established the second by the shedding of His blood on the cross. This fulfilled the prophecy of Jeremiah that the writer had quoted to them earlier.
When Jesus died, the veil in the temple that separated the people from the Most Holy place was rent. That allowed God’s children access to Him through Jesus, the High Priest who is now in the Most Holy Place, heaven. Christians can go to God at any time and ask for the forgiveness of their sins.