How did the responsibilities of the nobility differ from those of the clergy and peasantry during the High Middle Ages?

The clergy had responsibilities of their office, to the Church and their superiors. Secular clergy were responsible for the spiritual well being of their parishioners, and regular clergy had responsibilities within their orders, which could include anything from transcribing manuscripts to growing vegetables, washing dishes, or singing in a choir.

Peasants had the responsibility of doing their work, which was usually raising crops. They had to pay rent or do labor for their lords. Sometimes they had other responsibilities on their manors, but these varied. On some manors, the peasants had to elect their own reeves. It was possible they would be called to do duties for the manorial court.

The responsibilities of the nobility were most like those of the secular clergy, in the sense that they were responsible to their superiors but also had people for whom they were responsible. They had to support and obey they king and superior nobles, but they also had the responsibility to protect the peasants who lived on their manors. This went a good deal farther than the work secular clergy did, however, because it required them to attend to things that were physical, social, legal, military, official, where the secular clergy were only engaged in things spiritual. Unlike the nobility, the peasants and regular clergy usually had now one at a lower station for whom they had responsibilities.