Present subjunctive

The present subjunctive is identical to the bare infinitive form of the verb in all persons, including the third person singular (no final -s). It is usually used in formal or literary styles:

In certain set phrases

I see what you mean. Be that as it may, I can't agree with you. (even so, still)
Come what may, I will not resign! (whatever happens)
"I am a Jedi. Like my father before me." "So be it... Jedi." (it's okay with me, I accept this)
I do not want to bore you; suffice it to say, we finally got a full refund. (it is sufficient to say)

In exclamations that express a wish or hope

Rest in peace!
Bless you!
God save the King!

After adjectives such as IMPORTANT, ESSENTIAL, VITAL etc. 

It is/it was + adjective + that can be followed by a present subjunctive if the adjective expresses importance or necessity or that something should be done:

It is vital that everybody get there before the examination begins.
It is desirable that Mr Hanson hand in his resignation.
It is important that you be at home when the lawyers arrive.
It is essential that the car be waiting at the airport.
It is imperative that products be tested carefully.

In such sentences, the present subjunctive can be replaced with the less formal should + infinitive:

It is vital that everybody should get there before the examination begins.

After verbs such as INSIST, SUGGEST, RECOMMEND etc.

Mike insisted that I try his new muffin recipe.
I suggest that your cousin apply at once.
Carl was injured last week, and the doctor recommended that he not play in the next match.

Again, the present subjunctive can be replaced with should + infinitive in less formal styles:

I suggest that your cousin should apply at once.