Eckhart has a German word, Gelassenheit, that gets translated as detachment, release, or letting-be. It names a letting go of your own willing so that something other than your own will can act. In Eckhart's case that something is God.
The word sounds passive in English. It is not meant to be. Letting-be is closer to a kind of active unclenching: you stop running the show in your own soul so that God, whom Eckhart takes to be already present and already working, is free to act without your interference.
Letting go of your own will
Eckhart's German sermons come back again and again to a single demand: stop managing your inner life so that God can work in it. He asks for a kind of standing aside, rather than extra effort, more virtue, or more exercises.
Above all, make no claim on anything. Let go of yourself and let God act for you and in you as he pleases. This work is his, this Word is his, this birth is his, and all that you are besides. For you have abandoned yourself and gone out of your faculties and your own nature. God settles himself in your nature and powers when, stripped of all belongings, you go into the desert, as it is written, 'A voice crying in the wilderness.' Let this eternal voice cry on in you as it sweetly pleases, and be a desert yourself with respect to self and creatures.
Sermon 3: Being about the Father's business: the birth of God and the active life
The phrase "let go thyself" is the plain English of Gelassenheit. It means giving up the idea that you are the one who has to make the birth of God in the soul happen, while fully continuing to live your life. Eckhart's claim is that this birth happens on its own once you stop blocking it.
Let God be God in you
The clearest single statement of the idea in the Evans translation comes from Sermon 13. It is as close as Eckhart gets to a slogan.
Where the creature stops, there God begins. All God wants from you is for you to go out of yourself with respect to your creatureliness and let God be God in you. The smallest of creaturely images that ever takes shape in you is as big as God.
Sermon 13: Sharing Christ's nature and living without a why
Notice what is being let go of here: your attachment to being this particular, separate, self-managing thing, what Eckhart calls "thy creatureliness," rather than sin or the world as such. Once that attachment loosens, Eckhart says, God is simply what is there, present rather than merely visiting.
Why this is not passivity
It would be easy to hear letting-be as an excuse to do nothing, to drift, to stop trying. Eckhart does not mean that, and he is careful to say so. In Sermon 3 he distinguishes three kinds of intellect in us: one that is always active, one that is purely receptive when God is at work, and one that holds the other two together.
A person has an active intellect, a passive intellect, and a potential intellect. The active intellect is always in action, always doing something, whether in God or in a creature, for the honor and glory of God. That is its job, and that is why it is called active. But when God takes on the work, the mind has to stay passive. The potential intellect, in turn, relates to both of these, to God's action and the soul's passivity, to the soul's capacity to act. In one case the mind is active, when it is doing the work itself; in the other it is receptive, when God takes up the work, and then the mind must, indeed has to, stay still and let God act.
Sermon 3: Being about the Father's business: the birth of God and the active life
So there is real work involved, the work of withdrawing attention from distraction and self-concern. What stops is the work of trying to produce or force the birth of God by sheer effort. Eckhart's picture is less like a person asleep and more like a person who has stopped grabbing the wheel, while staying fully awake at it.
From Eckhart to Heidegger
Gelassenheit did not stay inside the sermons. Johannes Tauler, Eckhart's student, carried the word into the wider German mystical tradition, and later writers such as Angelus Silesius kept it alive. By the twentieth century it had become part of the German philosophical vocabulary that Martin Heidegger drew on.
Heidegger used Gelassenheit as the title of a 1959 set of reflections on thinking and technology. His sense of the word differs from Eckhart's: he is concerned with a non-grasping relation to things and with resisting the drive to master nature through technology, rather than with the birth of God in the soul. But he knew the mystical tradition the word came from, and the family resemblance is real: both are after a letting go of the will to control, in favour of letting something show itself on its own terms.
This is one of the more traceable lines of influence from Eckhart into modern German thought, alongside his effect on Tauler, Suso, and later on currents in German idealism.
Where the idea shows up in the sermons
The clearest statements are in Sermon 1, where Eckhart says the most anyone can attain in this life is to "remain still and let God act and speak in thee", and in Sermon 3, with its account of active, passive, and potential intellect.
Sermon 13 gives the sharpest single line, "let God be God in thee", in a sermon that also deals with living without a why. Sermon 17 adds a related thought: we leave God his glory by letting him work however and whenever he wants, while we stay, in Eckhart's words, idle and free.
On Detachment works through the same ground at treatise length. You can read it in Tractate 9.
Where to read next
Letting-be is close kin to detachment and to living without a why, and all three point toward what Eckhart calls the ground of the soul, the place where this letting go actually happens. If you are new to Eckhart, how to read Eckhart is a good place to get your bearings before going further.
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