cslink on Catholic Answer Forums, in a thread about the role of works in our salvation, brought up an analogy of a pipe with water representing grace and faith. I will take this one step further.
Consider a pipe (or aqueduct) which carries water from a source to a destination where it is used to power a device (a water-wheel, an irrigation system, etc.). The device (works) is accomplishing some task helping the town survive. The water (
So God saves us, by grace, through faith, in (do you have a better preposition?) works. Imagine the scenario above if the aqueduct fell short of the water-wheel: all this water getting to the town but not carrying out its purpose (grace and faith without works). All three parts are necessary for the salvation of the town.