Not every inward act is necessarily a primary question of creedal theology. Ethics studies qualities such as truthfulness and trustworthiness; spiritual formation can focus on purifying intention and reforming the inner self.
By contrast, questions about Allah's unity or how divine attributes are to be understood are directly creedal. Topics may overlap across disciplines, but the exact aspect being examined determines the scholarly setting.
Distinguishing creed, practical law and ethical formation helps organize learning without claiming they are unconnected elements of religious life.