“Anything that is in nature must be moved by something else.  Likewise this something else, in so far as it too is in motion, must also be moved by something else.  Similarly that too must be moved by yet another thing.  But this chain of events cannot recede forever, for if it did there could be no first mover and thus no other mover.  For second movers cannot move unless they are moved by a first mover, in the same way that a stick does not move anything unless it is moved by a hand.  In this way we must reach a prime mover which is not itself moved by anything.  And all understand that this is God.”

Thomas Aquinas
(Summa Theologica)

“Three things are necessary for the salvation of man: to know what he ought to believe; to know what he ought to desire; and to know what he ought to do.”

Thomas Aquinas