The argument from motion is the most detailed of the arguments that Aquinas presents, and is the one that will be analyzed in detail here. In brief, the concept is that everything that does not move itself, of which there are ample examples, must be moved by something else. Aristotle had argued that either there must be an infinite regress of movers, which he considered impossible, for reasons we will see, or else there must be finally an unmoved mover to end the chain.
The argument from causality might logically be the argument that underlies all the other here. It is the argument that every creature must be the cause of its own being or else be caused by another being. A being that is not its own cause is a contingent being, and in order to avoid an infinite regress, as with the argument from motion, one must finally postulate a being which is its own cause.
Aquinas defines being as not only the essence of God but also the proper effect of God, thus establishing God as the unique and direct cause of the being possessed by every finite thing. This argument also has the distinction of conceiving of God as the cause of being itself, rather than as the cause of motion or order or some other less essential attribute of being.
As summarized by Adler and his co-workers (II, 257), Aquinas wrote that all creatures, before