We are taught that Moses did not understand all of G-d's instructions how to make the Menorah, the Candelabrum, so G-d showed him an image of a fiery Candelabrum. But even so, the Candelabrum was still too complicated for Moses to envision, so G-d told him to simply throw the gold into a fire and the Candelabrum would miraculously take form.
Besides the Candelabrum's physical construction, what Moses found most difficult to grasp was how such a physical object could spread the light of Divine consciousness to the outside world. By showing Moses the fiery Candelabrum, G-d affirmed his hesitations. He informed him that indeed, using physical objects to spread Divine awareness in the world is impossible for us to do on our own. He therefore told Moses to cast the gold into the fire and that the Candelabrum would take form by itself.
Similarly, G-d requires us to transform all our material pursuits and possessions into sources of Divine light, but He also knows that we cannot do this on our own. All he asks is that we cast it all into the fire of our hearts--i.e., to let our love for Him permeate all we do--and He will miraculously do the rest.