does persistent work mean that we are to exert ourselves both day and night?no,that is not persistent work. that is labour without cessation. that is an impossibility.we must sleep.persistent work does not mean no rest,no food and no sleep.rather,it means no wast of time,or careful use of time for the purpose of improvement.that is to say,we are diligen if we know how to employ our time in order to reach a definite end.