Yes. He acts by the will, and not, as some have supposed, by a necessity of His nature because the intellectual and voluntary agent must precede the agent that acts by nature.
Because the Divine Being is undetermined, and contains in Himself the full perfection of being, it cannot be that He acts by a necessity of His nature -- unless He were to cause something undetermined and indefinite in being: and that this is impossible has been already shown (Q7 A2).
He does not, therefore, act by a necessity of His nature, but determined effects proceed from His own infinite perfection according to the determination of His will and intellect.
Because the Divine Being is His own intellect, effects pre-exist in Him after the mode of intellect, and therefore proceed from Him after the same mode.
Consequently, they proceed from Him after the mode of will, for His inclination to put in act what His intellect has conceived appertains to the will.