Jamieson, Fausset and Brown on Hebrews 9:7

7. once every year--the tenth day of the seventh month. He entered within the veil on that day twice at least. Thus "once" means here on the one occasion only. The two, or possibly more, entrances on that one day were regarded as parts of the one whole.

not without blood--(He 8:3).

offered--Greek, "offers."

errors--Greek, "ignorances": "inadvertent errors." They might have known, as the law was clearly promulged, and they were bound to study it; so that their ignorance was culpable (compare Ac 3:17; Ep 4:18; 1Pe 1:14). Though one's ignorance may mitigate one's punishment (Lu 12:48), it does not wholly exempt from punishment.