The Law is a shadow of the good things that are coming, not the real things themselves. It never can perfect the ones who are trying to draw near to God through the same sacrifices that are offered continually every year.
References for Hebrews 10:1
Otherwise, wouldn't they have stopped being offered? If the people carrying out their religious duties had been completely cleansed once, no one would have been aware of sin anymore.
Instead, these sacrifices are a reminder of sin every year,
because it's impossible for the blood of bulls and goats to take away sins.
Therefore, when he comes into the world he says, You didn't want a sacrifice or an offering, but you prepared a body for me;
you weren't pleased with entirely burned offerings or a sin offering.
So then I said, "Look, I've come to do your will, God. This has been written about me in the scroll."
References for Hebrews 10:7
He says above, You didn't want and you weren't pleased with a sacrifice or an offering or with entirely burned offerings or a purification offering, which are offered because the Law requires them.
References for Hebrews 10:8
Then he said, Look, I've come to do your will. He puts an end to the first to establish the second.
References for Hebrews 10:9
We have been made holy by God's will through the offering of Jesus Christ's body once for all.
Every priest stands every day serving and offering the same sacrifices over and over, sacrifices that can never take away sins.
But when this priest offered one sacrifice for sins for all time, he sat down at the right side of God.
Since then, he's waiting until his enemies are made into a footstool for his feet,
because he perfected the people who are being made holy with one offering for all time.
The Holy Spirit affirms this when saying,
This is the covenant that I will make with them. After these days, says the Lord, I will place my laws in their hearts and write them on their minds.
And I won't remember their sins and their lawless behavior anymore.
References for Hebrews 10:17
When there is forgiveness for these things, there is no longer an offering for sin.