Charles Ellicott Commentary Hebrews 10:31

"It is a fearful thing to fall into the hands of the living God." — Hebrews 10:31 (ASV)

The living God.—As in Hebrews 3:12; Hebrews 9:14, the exact meaning of the writer’s words is “a Living God”; and a reference to the first of these passages will clearly show what their force is here.

There can be little doubt that Deuteronomy 32:0, from which he has been quoting, is still in his thought. See Deuteronomy 32:40: I lift up my hand to heaven, and say, I live for ever.