This longer quote is quite fun, for reasons that would be evident, but to get it one has to bear in mind staid Heidegger's definition of Being in Being & Time (1927)
‘Being’ cannot indeed be conceived as an entity; enti nun additur
aliqua natura: nor can it acquire such a character as to have the
term “entity” applied ‘to it.
H4
16 years later the approach has changed. Hang on for the ride. From On Inception, § 3
Being-there is not without the steadfastness of the human.
But how, then, should beyng remain independent of the human? Just
because the human belongs to the grounding of the truth of beyng, this
does not mean that beyng depends on the human in such a way that beyng
would be established by the human.
So how does the human belong to beyng?
As steadfastness in the clearing, which intercepts the happen-stance
of beyng in its truth and safeguards the possibility that a world be
configured. In the whole domain of this preceding question, being is
immediately understood as what is constant. Being itself is not being
thought in its inceptuality. Thus, one places “value” on the inner
certainty of beings in their constancy, as if it was through constant
duration that they were most in being [am seiendsten]. What is
forgotten, though, is to ask with what right this claim about beings
might be made, and on what grounds being might be equated with
constancy.
What remains entirely beyond reach is the admittedly disconcerting
possibility that being, and not just beings, sometimes is not; and
that, if decided in this way, the essence of this not-being is such
that it even refuses the essential unfolding of the nothing. Thus,
being must indeed be entirely remote [abgeschieden] in its essence:
there can be no destruction or elimination of being, since it is
neither produced nor made.
So now it's down to the ambiguity of the 'existence' of being and the twilight dawn of inception.