Jamieson, Fausset & Brown

it remaineth--still to be realized. some must enter--The denial of entrance to unbelievers is a virtual promise of entrance to those that believe. God wishes not His rest to be empty, but furnished with guests (Luk 14:23). they to whom it was first preached entered not--literally, "they who first (in the time of Moses) had the Gospel preached to them," namely, in type, see on Heb 4:2. unbelief--Greek, rather "disobedience" (see on Heb 3:18).