Updated: Oct 15, 2022
On one occasion (MN 37), the Buddha is asked to summarize his teaching in a brief statement. And this is what he came up with: sabbe dhammā nālaṁ abhinivesāyā.
This brief statement is usually translated freely: 'nothing is worth clinging to.' But more literally it means: all (sabbe) realities (dhammā) [are] not suitable (nālaṁ) for fully (abhi-) settling in (nivesāyā).
All realities are unsuitable for fully settling in. Knowing this (and practicing accordingly) is enough to be fully liberated.
What is at play in this statement is the heuristic metaphor of detachment, being unestablished, not fixed anywhere, hence also free from attachment, appropriation, concern, craving, and the rest of the band.
Why is this so important? Because all realities are structurally uncertain and contingent (anicca), hence they can never provide an ultimately stable ground. Aiming at 'fully settling in' means wanting to live like a tree, which struggles to get as anchored as possible to its ground. According to the Buddha, this is an endless struggle, always leading to frustration.
Rather than be like a tree in this respect, one should aim at being like a bird, which can go everywhere, without leaving trace in the sky.
To use another metaphor, instead of struggling for getting even more stuck where we are, we should learn how to surf.