The well known hadith about changing an evil you witness with your hand if possible, or by your tongue if possible, or if nothing else, than hating the evil with your heart, is usually understood in terms of providing us allowances of accountability depending upon our ability. We are not responsible for whatever is beyond our capability. However, I think it is important to point out that implicit in the hadith are at least two prohibitions: First, a prohibition against doing less than our capability; and second, a prohibition on engaging in futile actions