There are Five Crucial Warnings in the book of Hebrews “about the peril of turning away from Christ” [New Open Bible KJV]. They can be used to divide and study the book:
This text is loaded with good teaching/preaching but v.25-29 contains the mighty summary which warns of judgment by refusing God, but, it also shows the supernatural blessings we presently have through the Kingdom of God...as we walk with the King and be a blessing!
So, the Lord compares the two covenants, the two mediators, the two locations of His presence etc. etc. but the power punch comes at the end of the chapter when He prophesies of His last appearance to man which is found in Revelation 6:12-17 when He opens the Sixth Seal. Then, men will fear Him!
In spite of this supernatural warning, most men will reject/refuse Him and will not repent (Revelation 9:20, 21, 16:11) in that day. But, some will turn to Him, both Jew and Gentile (Isaiah 19:16-25, 59:20, 21; Zechariah 13:9; Micah 7:15-17; Romans 11:25.26; Revelation 18:4, 5) through the God’s eternal mercy and ministry of the Day of the Lord priests unto God the 144 Thousand Sons of Israel (Psalm 110:3; Revelation 7:1-8; 14:1-5)!
Then, He will judge the ungodly and the earth during the Seven Trumpets, Seven Bowls, The Destruction of Babylon and the Battle of Armageddon as found in Revelation 8-19. But, His focus during the description of the New Covenant blessings is Jesus the Mediator and the Blood of sprinkling which is given in His summary vs.24. If you view this last warning as the end of His appeals to men before judgment, it becomes super-powerful in view of what will come upon mankind who refuse this series of warnings at the end of the age!