The archetype of the spiritual being is the angel. Since an angel has no body, it can never contain both good and evil in its being. Our sages therefore teach us that angels have no Yetzer HaRa (urge toward evil).
It is only in a physical being that both good and evil can exist together. Although they are at opposite poles spiritually, they can come together in the physical man. One reason why God created man in a physical world was to allow him to have full freedom of choice, with both good and evil as part of his makeup. Without a physical world, these two concepts could never exist in the same being.
The fact that good and evil can exist in the same physical space also allows good to overcome evil in this world. …In a purely spiritual arena, good could never come close enough to evil to have any influence over it. In the physical world, however, good and evil can exist together, and good can therefore overcome evil. Our sages thus teach us that one of the main reasons why man was placed in the physical world was to overcome the forces of evil. The Zohar expresses it by stating that we are here “to turn darkness into light.”
…An angel may be created initially with a vast storehouse of knowledge, but it has no way of increasing it, at least, not beyond its own sphere of activity. Thus, for example, we find one angel asking another a question: “And one [angel] said to the Man dressed in linen… ‘How long shall it be until the end of these wonders’” (Daniel 12:6)? One angel had to ask the other, because he could not know something outside of his own domain.
In the physical world, we can learn things through our five senses. We can hear, feel, smell, and taste. Our knowledge of things comes from our physical proximity to them. In the spiritual worlds, however, this does not exist. The only way that one can learn about a thing is to come into spiritual proximity with it. An angel cannot do this outside of his own realm.
Man therefore has an advantage over an angel. The very fact that he exists in this lower world enables him to reach up ever higher.