Gradual training

The Buddha sometimes described the practice (patipatti) of his teaching as the gradual training (Pali: anupubbasikkhā) because the Noble Eightfold Path involves a process of mind-body transformation that unfolds over a sometimes lengthy period.

Just as the ocean has a gradual shelf, a gradual slope, a gradual inclination, with a sudden drop-off only after a long stretch, in the same way this discipline of Dhamma (dhamma-vinaya) has a gradual training (anupubbasikkhā), a gradual performance (anupubbakiriyā), a gradual progression (anupubbapatipadā), with a penetration to gnosis only after a long stretch.

— Udana, 5.5

The emphasis on gradual training may be understood by the fact that, just as the human habits that give rise to suffering have been built up over a long period of time, those same habits similarly take a long time to undo, requiring a sustained effort achievable only with a genuine commitment to training.