This is an annual event that helps us refocus and give our "first fruits" to God.
God notices when you give up something to hear from him.
Join us if you can. There are many ways to fast. You can abstain from all foods and only drink water, juice and broth, You can do a Daniel fast (Daniel in the bible) which is no meat, no sweets, no bread, or you could try skipping meals and praying instead. If you need a breakthrough in your life or for someone else in your life you may want to consider trying this.
Here a great book that explains why and how