To express a comman

Content clauses expressing commands, requests, or suggestions commonly use the present subjunctive; such a clause may be introduced by a verb like propose, suggest, recommend, move (in the parliamentary sense), demand, or mandate, by an adjective like imperative, important, adamant, or necessary, or by a noun like insistence or proposal.

This use of the subjunctive is known as the mandative subjunctive or the jussive subjunctive and is said to be the most common use of the subjunctive in English.[1]

Note that the present subjunctive is used in these cases regardless of the actual time reference (which must be conveyed by the tense of the main verb):
I move(d) that the bill be put to a vote.
I ask(ed) that he be shown mercy.
It is (or was) necessary that we not forget our instructions.
Her insistence that he leave seems (or seemed) rude.

Some of these words have two senses: one that introduces a clause in the indicative, and one that introduces a clause in the subjunctive. For example, insist can mean assert forcefully and persistently, in which case it introduces the indicative (He insisted that he was innocent), or it can mean demand forcefully and persistently, in which case it introduces the subjunctive (He insisted that he be given the chance to prove it). This use is typically North American English. The verb in such constructions is sometimes mistakenly believed to be a sort of infinitive, contributing to the notion of the dying subjunctive.

Sometimes the verb of a main clause can be in the subjunctive mood, without any explicit word like the above; this carries the force of a third-person request. This is the usage found in many set expressions, such as God bless you.
America, America, God shed His grace on thee, and crown thy good with brotherhood ("America the Beautiful")
God save our gracious Queen

The traditional English text of the Aaronic blessing is cast entirely in the subjunctive, with jussive force:
The Lord bless thee and keep thee. The Lord make his face to shine upon thee. The Lord lift up his countenance upon thee and give thee peac