Hebrews 7:20-28 explains the superiority and permanence of Jesus Christ's priesthood compared to the Levitical priesthood. Unlike the Levitical priests, Jesus' appointment as a priest was not based on lineage but on a divine oath from God, signifying an unchangeable and eternal priesthood for Jesus (verse 20). This sets him apart as the guarantee of a better covenant between humanity and God (verse 22), unlike earthly priests who were subject to death. Additionally, while human high priests had to make daily sacrifices for their own sins before offering for others, Jesus did not need to make such offerings because He was sinless. Instead, He offered Himself once-for-all (verses 26-27).

Furthermore, this passage emphasizes that Christ's priesthood is characterized by perfection – holy, innocent, unblemished by sin – qualities which contrast sharply with those attributed to ordinary high priests under Mosaic law. Due to His sinlessness and sacrifice, Jesus is able to save those who draw near unto God through Him forever since He always lives making intercession for them (verse 25). The passage concludes by highlighting Christ’s ultimate qualification—His exaltation beyond all heavens where He now ever lives after being perfected fully.

In essence:

This passage underscores several key themes related to Christ's superior priesthood:

1) Its establishment through divine decree rather than legal requirement;

2) Its immutable nature as secured by divine oaths;

3) Its role in establishing an everlasting covenant,

4). It’s ultimately superior quality due mainly its completeness evidenced particularly through its absolute efficacy especially seen through his death burial resurrection ascension glorification

The message encourages stronger faithfulness among believers and leads them into living out life victoriously until they meet Him face-to-face.