[D-fendr]

Where does "outside time" come from? Aquinas doesn't mention time.

Not in the first cause argument, which is one of five including first mover. There's a whole section in Summa on "Whether God is eternal" in the form of objections and answers. I won't paste the whole thing here, but here's a part that refers to the first mover part of the cosmological argument of which the first cause argument is also a part.

The idea of eternity follows immutability, as the idea of time follows movement, as appears from the preceding article. Hence, as God is supremely immutable, it supremely belongs to Him to be eternal.

[kosta50]

The idea of eternity follows immutability, as the idea of time follows movement, as appears from the preceding article. Hence, as God is supremely immutable, it supremely belongs to Him to be eternal

How does he explain Creation?