Do not depend on the changing mind

"What state of mind do you want?
Even if you attain the state of mind you want,
It will change again.
Do not depend on the mind
which keeps changing."

Zuiken Sensei

Impermanence is the fundamental law of the world we live in and of our spiritual "realizations". If we believe in the permanence of this world, we will lose ourselves in it, in our desires about it. If we believe in the permanence of our spiritual "realizations" based on the false ego, we will lose ourselves in a false Enlightenment.
This is why, in our tradition, we take refuge in Amida Buddha in order to attain the true Enlightenment (birth in the Pure Land).
The ego cannot become free by himself.
Namo Amida Butsu