What did Kohut mean by mirroring in a child’s development?

In the context of narcissism, Heinz Kohut proposed that mirroring is a critical function performed by empathic parents to foster the healthy development of a child’s self.

According to Kohut, mirroring provides the child with necessary approval and enhancement, which allows them to develop a more realistic sense of self. When parents are empathic and provide this validation, it supports the maturation of the child's self-structure. Conversely, if a parent is unempathetic and fails to provide this mirroring, the child may experience a developmental arrest. In this state, the child’s self remains grandiose and unrealistic, as they were unable to progress through what Kohut considered a normal and necessary stage of development.1