Ps 135 14or the LORD will vindicate his people
and have compassion on his servants."
30  For we know him who said, "It is mine to avenge; I will repay," and again, "The Lord will judge his people."31 It is a dreadful thing to fall into the hands of the living God.

The Psalmist is teaching that God created life in establishing the creation covenant. But the wicked spread death through the worship of idols. God gave us the curses in order to oppose the spread of death. 8He struck down the firstborn of Egypt, the firstborn of men and animals. When man worships dead idols he is cursed with death. 8Those who make them will be like them, and so will all who trust in them. Man makes dead idols because he is cursed. He is blind to the living things of life. The Psalmist teaches that all men walk in darkness until God they experience the birth of Gods breath.

The author if Hebrews is teaching if they return to the ceremonial laws they will cursed. Those who redefine Gods law create idols. The returns for worshiping dead idols is death. God does not take out His anger with violence but He avenges by letting man remain in spiritual state of death. Although the OT church was under the ceremonial laws, yet salvation has always been by faith through Christ.  The ceremonial laws could be compared to the rules of our culture. We learn to follow the rules even tho we do not put them on the same level as the ten commandments and our salvation. The Psalmist never describes the life of God in the Psalms by including the daily rules of the ceremony. The law,covenants,curses, statutes, promises and decrees have always been the eternal language of salvation. The ot church had the same means to understand salvation as we do. The difference is that Christ made the axioms universal.He established them with greater authority. They were focused on an earthly inheritance even tho they had an eternal covenant. When Christ ascended to heaven ,He actually took possession of all things. So the nt covenant has greater authority. It is a dreadful thing to remain in darkness and be thrown in hell.