Prayer has the power to change nature! “Nothing can help a person break his unwanted desires except prayer!”
Prayer has the power to change nature (Likutey Moharan I, 216). This applies both to the forces of nature and to one’s own human nature.
Reb Noson once said, “Nothing can help a person break his unwanted desires except prayer. The reason for this is quite simple. Normally, a person who breaks his desires is left with two desires; just as when a person breaks something in half and is left with two pieces. But with prayer, we are able to rid ourselves completely of all our unwanted desire (cf. Siach Sarfei Kodesh 1-511).
A person who breaks his desires is left with two desires; just as when a person breaks something in half and is left with two pieces.
Prayer helps nullify a Heavenly decree before – and even after – it has been issued (The Aleph-Bet Book, Tefilah A:14). Once, when Reb Shimon’s son was deathly ill, he approached the Rebbe and asked him to pray for the child’s recovery. Rebbe Nachman, however, did not respond. Forlorn and without hope, Reb Shimon returned home. His wife understood well the implication of the Rebbe’s silence.
Yet, instead of despairing, she spent that entire night sitting at the infant’s crib and praying for her child. The following morning, when Rebbe Nachman saw Reb Shimon, he ran towards him with great joy, saying, “Look at the great power of prayer! Last night the decree was sealed. The infant’s death was imminent. And now, not only has the decree been nullified, but Heaven has granted him long life as well!” Tradition has it that Reb Shimon’s son lived close to a hundred years (Aveneha Barzel, p. 39 #60).
(Taken from the book Crossing the Narrow Bridge: A Practical Guide to Rebbe Nachman’s Teachings – chapter 8 – Prayer)