To afflict the soul means to fast. Every Jewish person knows that is the meaning of "afflict the soul." What is the soul? The soul is the part of the human being that is made up of the mind, the will and the emotions. The soul is the part of us that needs to submit to the Lord. The soul is the part that will go it's own way. The soul is the part that can be wounded or can be encouraged.
40 Days of Prayer and Fasting – Day 31 -Afflict the Soul
Revealed Ministries 