Let us assume that we have a few pieces of land, and we plant one kind of grain in each of them, and create different climate conditions for each of them. We block the light of the sun in one plot, leave the other without water, leave the weeds in the third, etc. We will see how much the external elements such as the sun, water, temperature and weeds, affects the development of the plant.
Although the internal plan of development is given in advance, its implementation is influenced by external conditions. Thus we arrive at the conclusion, as we will see later on, that if a person finds an optimal environment, one that supports his spiritual development, he can realize his birth attributes more effectively, meaning utilize his first and second elements to the maximum.
http://www.youtube.com/watch?v=Oyz7e8iQ6Uo