What are the political and spiritual differences between feudal and slave societies?

In the political sphere, the differences between the slave system and the feudal system were as follows: the slave system implies the presence of a disenfranchised class of slaves with the state, which appeared as a result of the conquest of the peoples of other countries, for which it was necessary to wage exciting wars, and under the feudal system the function of slaves was performed by serfs, who were citizens of the same country.
In the spiritual sphere, there are practically no differences between the feudal system and the slave-owning system: both slaves and serfs were the property of their masters and had no rights.