Creatio ad nihilum?

Creatures by definition depend on something outside themselves to remain in existence.  Does this then mean that they are in danger of slipping into non-existence?  Do they, as one scholar suggests, retain “a potency for nonbeing” and do they “risk passing out of existence, if separated from the source of its being”?

The qualifying conditional phrase tells it all: Can any creature be separated from the source of being?  Does God, once creating, give up on it?  And, does the creature have “potency toward non-being”?  Where would that come from?  It seems that it could only come from God, since all its potencies come from God.

So creatures neither sustain themselves by their own powers, nor are they in danger of slipping into non-existence “by their own powers.”  Their being or not is utterly in the hands of God.  Creatures are neither puttering along on their own, nor straining against God to snuff themselves out.  Whether they live or die, they are dependent on the Lord of life and death.