Yes. I think one can get a good idea about this point of having a “stable mind” (like a post embedded firmly in the ground) after realizing the true meaning of the First Noble Truth on suffering or Dukkha Sacca.
– That understanding comes with the comprehension of Tilakkhana: anicca, dukkha, anatta.
I just posted the following document in another thread at the forum. You may want to read that too:
The Way to Nibbāna