Activity and creating are not the same thing.
Miss Paula Haigh, Thomist scholar explains:
The Thomistlc relation of creation gives no support to a theory of continuous creation
St. Thomas says:
“Creation places something in the thing created according to relation only; because what is created is not made by movement or change. For what is made by movement or by change is made from something pre-existing. And this happens, indeed, in the particular productions of some beings, but cannot happen in the production of all beings by the universal cause of all things which is God. Hence God, by creation, produces things without movement. Now when movement is removed from action and passion, only relation remains. Hence, creation in the creature is only a certain relation to the Creator as to the principle of its being (its very existence). Nor is it necessary that as long as the creature is, it
should be created.” (ST, I, Q 45, a 3)
This Thomistic relation of creation, then, is nothing other than that radical and absolute dependence of every creature upon the Creator for its very existence. It is the passive aspect of that action of preservation whereby God, of necessity, “Does not preserve all things in existence otherwise than by continually pouring out existence into them.” (ST, I, Q 104, a 3) And all creatures receive this gift of existence in a limited manner defined by their essence or nature. The relation of creation is analogous, in a faint manner, to the relation of the child to the parent that continues throughout time.
And so, the creation of all things in the beginning must be distinguished from the relation of creation which remains in the creature as a condition and state of radical dependence upon God and is a result of having been created, either 1) in the beginning during Creation Week, as is the case with all the corporeal kinds, or 2) at the moment of human conception when, it is assumed by most theologians today, the human soul is created directly and immediately by God in time but not in any way as a process of the temporal nature of time,
As St. Thomas asserts:
In the works of nature, creation does not enter but is presupposed. (ST, I, Q 45, a 8) The theory of “continuous creation” robs creatures of their own proper action as secondary causes or else it robs God of His proper Creative Action in the beginning, and so it is to be rejected as false.