In the Gemara (Bava M’tzia 59a), we learn that since the destruction of the Beis HaMikdash the gates of t’filah have been closed. However, our sages teach us that the power of t’filah from the heart, combined with a complete trust in Hashem and awareness that He is the One in control of the world, can break through all the gates of Heaven, and there is nothing that can stand in its way. There is nothing stronger than prayer with closeness and love of Hashem; it breaks all barriers and can change what has been decreed.