If there was a 1st moment in time.

[surreptitious57]

Virtual particles come into existence from a state of absolute nothing although such a state cannot persist because of quantum fluctuations. And they are called virtual not because they do not exist rather
because they only do so for an infinitesimal period of time. There is no cause that precedes their existence. The law of cause and effect is a law pertaining to classical physics and not quantum mechanics

The Universe though did not come from absolute nothing. The singularity it is supposed to have come from is defined as a point of infinite density compressed into a space of zero volume. Not only is this physically impossible but it is also forbidden by quantum mechanics. So a singularity cannot be absolute but it can though be asymptotic.  This is a line which gets infinitesimally closer to another line with
out ever actually touching it. Now if the Universe came from that the singularity could exist but it would not experience time. And is why physics can currently only go as far back as the Big Bang and why
t = 0 provisionally begins at that point. It does not mean time did not exist before then but that physics cannot explain what happened before it. New physics is needed for such an explanation. That new physics would be a theory of quantum gravity. However it cannot currently be quantised because all the equations reference infinities which make no sense for probabilities can only exist between 0 and l

The two originators of the Big Bang Theory in 1970 namely Penrose and Hawking have both subsequently discarded it and nowadays no physicist thinks the Universe came into existence from absolute
nothing 13.72 billion years ago. The idea is completely scientifically redundant and there is no scientific reason as to why the Universe cannot extend infinitely into the past from a temporal perspective

It is also important to remember when physicists talk about the Big Bang they only mean local cosmic expansion not the Universe per se
And so to avoid confusion the latter is usually referred to as the Multiverse even though the actual definition of Universe is ALL THERE IS

[Anomalocaris]

It seems to me When people attempt to use throw about concepts such as nothing comes from nothing, or something comes from some thing, they are really attempting to assert that things not just can only, but also must always, assume guises we feel comfortable associating with existence.

Quantum mechanics say all what are colloquially called things are emergent properties of underlying quantum fields, even causation is but an emergent property of the behavior of the underlying quantum fields.   When Krause said universe from nothing, he didn’t mean quantum fields from nothing.  He meant emergent properties we associate with matter, energy, time and space need not have always been there even if the underlying quantum field, to the extent that the emergent concept of time allow us to visualize “always”, seem to fit out idea of always being there.

We seem to have a mantle Hang up over the idea that conventional concept of mass, energy, time and space are not fundamental.   We don’t reflexively regard a notional quantum field that has not yet perturb itself in a manner that causes mass, energy, time or space to emerge as already being something.   Hence intuitively we rebel against mass, energy, time and space not not having arisen from something more familiar.