Peace is a fruit of the Spirit.
The deepest longing of man´s heart is actually for peace. In everything we do, whether good or bad, we seek peace. When a person loves, looks for and experiences peace, or even when he hates and wants revenge, he seeks peace. When he stays sober or fights against addiction, he seeks peace. When he becomes drunk, he also seeks peace. When he fights for his life and the lives of those he loves, he realizes peace. Even when he raises his own hand against himself and commits suicide or kills someone, again he seeks peace. Therefore, every decision of man is, in its essence, a decision for peace. Clearly when good is being done, personal peace and the peace of others are being realized. On the other hand, when evil is being committed, it is a search for one´s own peace at the expense of the peace of others.
Looking at it from yet another perspective, we can see how often we loose peace because we are egotistical, selfish, envious, jealous, avaricious and consumed by power and honour. Experience confirms that through fasting and prayer, evil, egoism, and selfishness are overcome; the heart is opened and love and humility, generosity and goodness grow. Thus, true conditions for peace are realized. Whoever has peace because he loves and forgives also remains spiritually and physically healthy. He remains capable of shaping his own life in a manner worthy of man, who is the most exalted of God´s creatures. Through fasting and prayer, human needs are also diminished and brought to proportion. Also by this, conditions for peace along with a proper relationship with others and material things are being created.
This is why a misunderstanding comes about when fasting is experienced in a negative way, as a renunciation of something: namely, when its benefit is not recognized on the spiritual level. For this reason, it is not possible to speak about replacing fasting with good works or anything else. In this context, we can understand why peace is always promised after conversion and after fasting and prayer.
It is, therefore, through fasting that a person comes to understand what he must fight against in himself. In this way, our subconscious is also freed from everything that drives us to restlessness and disorder. The soul then becomes still and conditions for peace are realized. The following text beautifully presents an image of this battle:
“When a king wants to occupy a city of the enemy he first seizes the water source and stops every supply. When the inhabitants begin to die from hunger and thirst, they surrender to him. This is what it is like with physical cravings: when a religious comes against them with fasting and hunger, the enemies of the soul lose strength.”
Experience clearly confirms that without a battle against internal enemies of peace, it is not possible to come to peace. This is why fasting is a very tried and tested means. This is also why it is not accidental that all of the prophets, together with Jesus and then the entire Church tradition, have called man to fasting and prayer, so that he may open himself to true peace. The problem is that man is inclined to follow the way of false prophets who promise an easy peace that actually does not exist.
Cf: Fr. Slavko Barbaric: Fast with the heart, Informativni Centar „Mir” Medjugorje, 2000