However, Imma overcomes this with her sweetening power. This is the underlying mystery of how Imma completes Zeir Anpin, becoming “bone of his bones and flesh of his flesh” (cf. Genesis 2:23; see Etz Chayim, Shaar HaMochin ch. 1). For Zeir Anpin is intrinsically on the side of stern Judgment, while Imma gives him a share of the power of mitigation that is in her intrinsic nature. To the exent that Imma increases this sweetening influence, so the severity of Zeir Anpin is mitigated.
And this is the key to the concept of the different mentalities (מוחין, mochin) of Zeir Anpin in immaturity (קטנות, katnut, “smallness”) and maturity (גדלות, gadlut, “greatness”). In the stage of immaturity, only the external aspect of this function of Imma is given to Zeir Anpin, causing minimal mitigation. However, as Zeir Anpin attains greater mental levels, the severity of the Judgment becomes increasingly mitigated, until it becomes completely sweetened.