Why did Isabella and Ferdinand use the inquisition to suppress heretics?

Isabella and Ferdinand used the Inquisition to suppress heretics primarily to unify Spain under Catholicism and strengthen their political power. By targeting non-Catholic groups, such as Jews and Muslims, they aimed to eliminate religious dissent and consolidate their authority. The Inquisition also served as a means of controlling the population and ensuring loyalty to the monarchy, thereby solidifying their rule in a diverse and fragmented society.