When a person lacks the capacity to generate new emotions of awe and love for Hashem, he has another path. He can awaken his instinctive love, which is embedded deep within his soul. This powerful love is innate to the Jew and includes within it an element of fear. Being mindful of his deep desire to attach to Hashem, a Jew can then use his awareness to perform a mitzvah. This intention then becomes the soul of the mitzvah, and is analogous to the soul of the animal whose love and fear are not a product of its intelligence and choice, but rather are a natural instinct.