25 On the seventh day hold a sacred assembly and do no regular work.

Read Numbers 28:25 Using Other Translations

And on the seventh day ye shall have an holy convocation; ye shall do no servile work.
And on the seventh day you shall have a holy convocation. You shall not do any ordinary work.
The seventh day of the festival will be another official day for holy assembly, and no ordinary work may be done on that day.