The "mountain" symbolizes "raw nature", our God-given environment. At the opposite extreme stands the "house", a structure entirely made by man, albeit with materials derived from nature. In between stands the "field" - land or some other natural resource that man has to manipulate in order to produce his food and other needs. In today's world, the "house" - symbolizing the man-made urban civilization in which we live - is seriously out of harmony with the wider natural environment, and our patterns of production and consumption are causing appalling damage to the environment, but the Torah teaches that this can be rectified and that mankind will attain new and lasting harmony with nature, just as soon as we realize that the key lies in envisioning and constructing the Sacred House - the Temple of God in Jerusalem.