What is a knights job?

A knights job is to protects it's people

ANSWER:

A knight's job was to protect the interests of the Lord or Ruler he worked for, by any means necessary. Many knights used their power over the serfs and vassals to their own benefit, and many were very cruel and power-hungry. Things eventually got so bad that the Pope created a "Crusade" for them to go on to keep them busy and give them something to do other than tormenting the common people.