After verbs of commanding.
This subjunctive is very frequent after verbs of commanding.
See that there be no traitors in your camp.—Tennyson.
Come, tell me all that thou hast seen,
And look thou tell me true.
—Scott.
See that thy scepter be heavy on his head.—De Quincey.
VIII. Concessive Clauses.
229. The concession may be expressed—
(1) In the nature of the verb; for example,—
Be the matter how it may, Gabriel Grub was afflicted with rheumatism to the end of his days.—Dickens.
Be the appeal made to the understanding or the heart, the sentence is the same—that rejects it.—Brougham