…and the Kindness fortified… As the force of Judgment subsides, so the Partzuf increasingly shines out with Kindness. If Judgment had been made to subside all at once, all the lights would have immediately brought forth all their powers at once, leading to instant maturity. However, this is not the way it is, because the gradual order is preserved throughout everything. Accordingly the Judgment subsides gradually, as the proposition goes on to state.
…and it continues to subside little by little… This is also the mystery of how the Mental Powers of immaturity are pushed down from the head of Zeir Anpin into his body, and with each successive stage in their descent mature Mental Powers enter in their place, as discussed in the teachings of the ARI (Etz Chayim, Shaar HaMochin deKatnut ch. 3).