of their existence upon a cause. How so? We have already said that the cause has no effect upon the prior non-existence, for the only reason that non-existence obtained was the absence of the cause. Nor does the cause act upon the fact that this existence comes after non-existence, for it is impossible for matters to be otherwise: originated things, by their very nature, can come to be only after not having been. Thus, what is connected to the cause is the sheer existence that is in itself merely possible, not anything having to do with its being subsequent to non-existence or the like. Hence this connection must endure continually, and the causes that bring a merely possible thing into existence must remain together with the effect inasmuch as it is characterized by existence.”

I say:
This is a reference to his earlier assertion that the reason an entity needs an agent is its contingency, not the fact of its origination in time. We have no intention here of probing that point, for elsewhere we have made clear that dependence on an agent is not produced by any further cause at all; rather, the very entity that is dependent is so by its own essence, not by one of the attributes of that essence. Everything apart from God is, by its very being, needy of Him; it is inconceivable that it could ever cease to be needy of Him. Its poverty before God is not due to some factor that made it so, but springs from its very essence.