Hands and legs are two opposites. “Hands” means what we obtain, from the words, “for a hand obtains.” Raglaim [legs] are Meraglim [spies], meaning that we still do not know what is there and we are now going to spy on the land.
Man’s main advancement is through the legs, who walk from this place, implying that they always criticize the actions, to see if the land is good or not. Then, by overcoming, we come to the other end, which is regarded as “hands,” meaning that the “hands of Kedusha [holiness]” are regarded as being above reason. Conversely, the hands of the Sitra Achra [other side] are “hands of knowledge.” This is why we need both hands and legs.