A hortatory subjunctive (sometimes called a “volitive subjunctive”) is always a first person verb, plural, and subjunctive mood. (GGBB p464 or Robertson p930) It is used in exhortations, the speaker thus exhorting others to join him in the doing of an action. It almost has the force of an imperative except that the necessity is located in the speaker rather than in those addressed. See also cohortative.