Hebrews 3:19 - Ellicott's Commentary On The Whole Bible

So we see. — Rather, And we see. It is not the general conclusion that is here expressed; but, as in Hebrews 3:18 we read of the oath of exclusion, this verse records the fact, and also states the cause under an aspect which is most suitable for the exhortation which is in the writer’s thought. There is force in “could not enter”: — not only disobedience, but cowardice and weakness, sprang from “unbelief.”