Initial awakening to our true nature is followed by gradual cultivation which is the gradual removal of the dross which made our true nature seem absent. This is why Zen master Heze Shenhui (684–758) said that sudden enlightenment is to be followed by gradual cultivation. Entrance into ultimate reality is always sudden as a result of direct intuition.
After intuition follows the cultivation of what we have intuited. One doesn’t gradually enter into their true nature as is 5% now, maybe another 6 or 7% a year or so later and so on. About gradual cultivation, Zen master Mengshan 蒙山 said:
“This matter is like peeling a pearl. The more you peel it, the more radiant it gets. The brighter it gets, the purer it gets. Peeling a single layer is superior to several lifetimes of gongfu [effort].”
But first you have to find your great pearl! One must open up many, many oysters until you find the one with a most priceless pearl. Nor is there anything gradual about finding such a special pearl—you either find it or you don't. There are many oysters and few great pearls.
Mengshan is also right about "peeling a pearl."