The purpose of Creation is for man to understand and cleave to Hashem. This understanding is referred to as אור, light. The entirety of the body of the person contributes to his minds ability to achieve this comprehension. They are the כלים, vessels, which facilitate the assimilation of the light.
There are two types of כלים. The limbs of a person serve him to achieve these comprehensions. So too, all other aspects of Creation work to this end as well. The distinction is that a person's limbs are direct contributors to a person's serving Hashem, whereas everything else does so in an indirect manner and are more distantly connected to the person's ability to serve Hashem.
This serves as a way to understand the distinction between the inner and outer vessels. Those which are direct are referred to as the inside. The indirect ones are the outside.
There are two types of כלים. The limbs of a person serve him to achieve these comprehensions. So too, all other aspects of Creation work to this end as well. The distinction is that a person's limbs are direct contributors to a person's serving Hashem, whereas everything else does so in an indirect manner and are more distantly connected to the person's ability to serve Hashem.
This serves as a way to understand the distinction between the inner and outer vessels. Those which are direct are referred to as the inside. The indirect ones are the outside.