2. What is in any being, and comes of the agent that produced it, must be the actuality of that being: for it is an agent's function to make a thing be in actuality. But, as shown above (Chap. XV), all other substances have their existence of the prime agent: indeed their being created substances consists precisely in this, that they have their existence of another. Existence itself therefore is in these created substances as a sort of actualisation of the same. But that in which actuality is received is potentiality: for actuality is such in relation to potentiality. In every created subsistent being therefore there is potentiality and actuality.
2.52 : That in Created Subsistent Intelligences there is a Difference between Existence and Essence
2.55 : That Subsistent Intelligences are Imperishable