Just as Jesus presupposed that His disciples would pray, He does the same here by saying, “When you fast…” Fasting is a spiritual discipline that requires not partaking of one of our primal physical needs and desires, food, for a defined amount of time. In doing so, we are saying to God, “Hearing from you in prayer and reflection on your word is more important to me than even eating.” Fasting is something that He did not want us to misunderstand.