"There are two aspects to serving God.
The first is to do His will.
The second is to make oneself able to see the Divine as fully as one is able to see with one's eyes.
A person achieves this by overcoming the images created by the complex of the body and animal soul's sensory organs.
He must conqueror and cast down the animal soul, breaking down and removing the sensory images that prevent him from seeing the Divine light.
When a person successfully overcomes this structure of falsehood, the world’s illusions and its material nature, his Divine soul can perceive the Divine light with a vital and genuine feeling, existent and active within him at every moment of existence."
From Understanding the Tanya by Rabbi Adin Steinsaltz, Chapter 29, p. 63