So this holy life, Monks, does not have gain, honor, and praise for its benefit, or the attainment of virtue (moral conduct) for its benefit, or the attainment of concentration for its benefit, or wisdom and vision for its benefit. But it is this unshakeable liberation of mind that is the goal of this holy life, its heartwood, and its end.

Suppose a man needing heartwood, seeking heartwood, wandering in search of heartwood, came to a great tree standing possessed of heartwood, and cutting off only its heartwood, he would take it away knowing it was heartwood.

Then a man with good sight, seeing him, might say: This good man knew the heartwood, the sapwood, the inner bark, the outer bark, and the twigs and leaves. Thus, while needing heartwood, seeking heartwood, wandering in search of heartwood, he came to a great tree standing possessed of heartwood, and cutting off only its heartwood, he took it away knowing it was heartwood. Whatever it was this good man had to make with heartwood, his purpose will be served.

(Reference: MN 30)

In this Teaching from Gotama Buddha, he shares how the goal of The Path to Enlightenment is “unshakeable liberation of mind”. An “unshakeable liberation of mind” is the way Gotama Buddha described Enlightenment.

As a Practitioner trains the mind to attain Enlightenment, it is no longer possible for the mind to be shaken up by anything. All discontentedness is eliminated, and the being will no longer experience any discontent feelings.

Instead, the mind will be peaceful, calm, serene, and content with joy - permanently. The mind will be relaxed and calm yet attentive and alert at all times.

The mind will have deeply understood and be practicing The Natural Laws of Existence, the truth. In understanding the truth, a Practitioner can no longer be misled or convinced otherwise because they have already seen the truth and know the truth. The mind is unshakable.

There are multiple topics in your life where you might have seen the truth, and no one could convince you otherwise. For example, you have seen the truth of The Natural Law of Gravity. You know it exists and that it affects everyone and everything on planet earth. There is no one that could convince you otherwise that this natural law does not exist.