There is a sense in which today's text is an explanation of the quick reference our writer made to the construction of the "tent" or tabernacle back in Hebrews 8:5 - "They serve a copy and shadow of the heavenly things. For when Moses was about to erect the tent,he was instructed by God, saying, See that you make everything according to the pattern that was shown you on the mountain."
At that point our writer was concerned to prove the tabernacle approach to God was prescribed by God Himself in all those construction details. No one had access to God on his or her own terms. And our writer has a present-day reason for these old covenant tabernacle references. In the very same way God restricted access to His presence to the tabernacle in the old covenant He has restricted access to His presence through Jesus the Christ in the new covenant. Jesus, the Christ, is now the prescribed new covenant approach to God. There aren't many, or even several, new covenant mediators on our behalf for entrance into God's holy presence.
In this way our writer joins the unanimous voice of every New Testament writer, along with the only recorded words we have from our Lord Himself - "No one comes to the Father but by me!" Father God has consistently revealed a divine intolerance to religious devotion denying, or even diminishing, the High Priestly access provided through Christ alone.