The Buddha taught that this process matures at its own rate. Having reached this level of practice, we allow it to develop according to our innate capabilities, spiritual aptitude and the merit we’ve accumulated in the past. But we never stop putting eort into the practice. Whether the progress is swift or slow is out of our control.
Where did the Buddha state this? I’ve tried to find this to no avail. I’m wondering if this has to do with the “seeds” of kamma that Thanissaro Bhikku mentioned in various talks and in The Karma of Mindfulness on pages 56 and 76.
“Mendicants, form is not-self. For if form were self, it wouldn’t lead to affliction. And you could compel form: ‘May my form be like this! May it not be like that!’. But because form is not-self, it leads to affliction. And you can’t compel form: ‘May my form be like this! May it not be like that!’
And the same is said for the other aggregates - feeling, perception, choices and consciousness.
AN4.162:1.1 ff: “Mendicants, there are four ways of practice. What four? Painful practice with slow insight, painful practice with swift insight, pleasant practice with slow insight, and pleasant practice with swift insight.
Then the Sutta proceeds to explain how, dependent on the strength of bad qualities on one hand and one’s spiritual faculties on the other hand, progress develops slower or faster.
See also the entire chapter; the same thing is mentioned in other Suttas too.
A common misconception and there is a danger of passivity:
" One of the most striking features of mindfulness as taught in the modern
world is how far it differs from the Canon’s teachings on right mindfulness.
Instead of being a function of memory, it’s depicted primarily—in some cases,
purely—as a function of attention to the present moment. Instead of being
purposeful, it is without agenda. Instead of making choices, it is choiceless and
without preferences."
[…]
" If you view these things as simply arising for you to observe
passively as they pass away of their own accord, you’ll miss the hidden role that
intention plays in actualizing them from the potentials of your past actions."