Idem nefastos dies fastosque fecit, quia aliquando nihil cum populo agi utile futurum esset. He also established days on which no public business could be transacted and days on which it could, because sometimes nothing profitable ought to be done with people.
I'm having trouble with futurm esset. What construction is it? The closest thing I can find is the future active infinitive, but with that I've only ever seen the future active participle followed by esse.