Four Hundred Texts on Love (Fourth Century) 1

12.  Divine grace cannot actualize the illumination of spiritual knowledge unless there is a natural faculty capable of receiving the illumination. But that faculty itself cannot actualize the illumination without the grace which God bestows.

This text captures the heart of the synergy between us and God. The work is done by God, healing us with his grace. But that grace requires that we turn our will toward God.