 The ultimate end of human life is felicitas or beatitudo… So the main concern of law [including the natural (moral) law] must be with directing towards beatitudo. Again, since every part stands to the whole as incomplete stands to complete, and individual human beings are each parts of a complete community, law’s appropriate concern is necessarily with directing towards common felicitas … that is, to common good. (ST I-II q. 90 a. 2.)