Hello, Christian. Here is an explanation. By God's grace, it will be helpful.
First, I will add some extra information into the text, and then expound.
Heb 9:23 "It was therefore necessary that the patterns of things in the heavens [the "patterns" being the Mosaic ceremonial vessels of the tabernacle] should be purified [made ready to be used by the priest on behalf of the people] with these [sacrifices]; but the heavenly things themselves [God's grace unto men, and his presence in heaven] with better sacrifices than these.
The use of this word translated "purified" is interesting, because it describes the [b]legal preparation[/b] of the vessels used for God's service in the temple. The vessels were not themselves sinful, but in order for the priest to lawfully use these vessels to represent guilty people before God, sacrifices had to be made and applied to the vessels as a sign of the true atonement which guilty people need to stand righteously before God's holiness.
Because of God's holy standard, sinful men cannot justifiably enter and enjoy God's presence without having been cleansed of their sin. This cleansing came, once for all time, through the offering of Christ on the cross. Christ's blood prepares the way for men to enter the holiest of holies, God's presence. Just as blood from the animal sacrifices was applied to earthly temple vessels to justify their use on behalf of the sinful nation of Israel, even so the means of saving grace are secured by Christ's blood on behalf of his elect.
I understand the heavenly vessels to be the means of saving grace which work together to save men - such as election before time [Eph 1:4], the washing of regeneration unto faith [Eph 2:2,5-9], the application of Christ's death and resurrection to our spirits [Eph 2:13]; the adoption and ushering into the holiest of holy places with the Father [Eph 1:5, 2:14]. Christ is our priest who administers salvation, using these spiritual implements to bring us to right standing with God.
However, it would not be right for Him to apply these heavenly gifts to sinners, no, it would be impossible, unless the use of these means had been justified - "purified" - through the spilling of His blood on our behalf. This is what makes God both just, and the justifier of sinners.
Does this make sense?
By the way, Erin just finished a new CD. I'll let you know when it's online.