A vassal and a knight were two distinct roles in the feudal system, but they could overlap. A vassal was someone who pledged loyalty and service to a lord in exchange for land or other benefits. This relationship was formalized through a ceremony known as homage.
A knight, on the other hand, was a warrior trained in combat and chivalry. Knights often served as vassals to lords, providing military service in exchange for land or other rewards. However, not all vassals were knights. Some vassals were simply landowners or administrators who did not have the military training or responsibilities of a knight.
In summary, while a vassal could be a knight, not all vassals were knights. The roles were related but not identical.