Producing - Acting

"... And this is why a natural agent does not produce being simpliciter, but instead produces being that preexists and is determined to this or to that, e.g., to this species of fire, or to whiteness, or to something of the sort. And because of this a natural agent acts by moving, and so it requires matter, which is the subject of the change or motion; and for this reason a natural agent cannot make something from nothing. ..." [4]

[4] Thomas Aquinas, de potentia dei", ques. 3, art. 1

Source: University of Notre Dame