A tremendous earthquake, apparently coupled with volcanic action, provided an awe-inspiring setting for the inauguration of the Law covenant at Sinai. (Ex 19:18; Ps 68:8) Jehovah had a direct hand in this display of power, for he spoke out of the mountain by means of an angel.​—Ex 19:19; Ga 3:19; Heb 12:18-21.

The apostle Paul uses as an illustration the awe-inspiring display at Sinai, comparing it with the greater and more awesome assemblage of the Christian congregation of the firstborn before God and his Son as Mediator at the heavenly Mount Zion. He goes on to follow through with the illustration of the earthquake that took place at Sinai and gives a symbolic application, encouraging Christians to continue serving in courage and faith, realizing that the Kingdom and those who hold on to it will be able to remain standing while all other things of the symbolic heavens and earth are shaken to pieces.​—Heb 12:18-29.