How did the relationship of lords and knights exemplify the system of feudalism

The system of Feudalism is based on the number of vassals or knights that would work under the king. If the king has more knights, then he has more power because he has the manpower that can defeat other kingdoms. So if the knights would have a good relationship with the lords, then they will want to serve the nobility and is willing to fight for the nobility. Maintaining a good relationship with the knights is very important because it is the number of knights that can give the king his power.