Why is Christ's role as our High Priest important?

In Hebrews 1:3, we see that after purging our sins, Christ 'sat down on the right hand of the majesty on high,' signaling the completion of His sacrificial work. The significance of this role lies in His unique mediatorial function; as the perfect High Priest, Jesus meets the requirements of both divine justice and mercy. He offers Himself as the Lamb of God, fulfilling Old Testament prophecies and sacrificial systems, thus providing a once-for-all atonement. This means that believers have constant access to God through Him, enrolled in His grace, which assures us of our righteousness before God. His priestly intercession keeps us secure in our salvation, showing that His work continues on our behalf.