Have you ever been roused from sleep with your heart pounding, feeling anxious, embarrassed, or guilty? Then you know that dreams can be very powerful and thought provoking. They can make us worry, cry, or perhaps even scream. Why is it that such a powerful part of our brain seems to be completely out of our control? Freud and Jung opened a study of dreams that still fascinates psychologists today.
There also exists a mystical side of dreams that remains incomprehensible. Many say they’ve seen a loved one who has passed away appear in a dream. After my brother died, I saw him in my dreams on a number of occasions. Did my mind merely conjure up his image, or was it a mystical experience? Many claim to have dreamed an event that later actually occurred. Can this really be so?
The Kabbalah has a unique and specific attitude towards dreams that opens up another dimension for us. The Bible makes a clear connection between dreams and spirituality. God communicated with Avimelech, the king of Egypt, in a dream when he had taken Sarah captive from Abraham (Genesis 20:3,6). We also see that Jacob had a dream about a ladder that was laden with messages (Genesis 28:12). Farther on we see Joseph not only has prophetic dreams, but also the ability to interpret the dreams of others, such as Pharaoh’s baker and wine steward. This underscores the potential for prophetic information to be hidden in the dreams of everyone. Divine communication and prophetic information for the holy and for the average man await us in our dreams.
A direct connection exists between dreams and spirituality. The questions of how and why remain. The Kabbalah explains the mechanics of this connection.
“The Creator designed us so that the Divine part of the soul can be somewhat detached during sleep from its physical bonds. The higher aspects of the soul are elevated and separated from the body. One aspect of the Divine part of the soul remains with the lower part of the soul. The detached aspects move about in certain spiritual realms and have some involvement there, either with the spiritual forces behind nature, or with prosecuting angels or demons. They experience what is determined for them in this realm. Sometimes, while above, they can transmit information received back down to the soul that remained behind. This awakens the imagination and causes mental imagery. Sometimes it’s true information, sometimes false, depending on the source of that information. The information itself enters the imagination and gets entangled in other thoughts, desires, and other physical phenomena that confuse the transmission. Other times it may come back clearly.” 
During the waking hours, the soul in its entirety is bound to the body. While the body sleeps, the soul separates and has contact with the spiritual world. Since many future events have been decided in the spiritual courts, that knowledge can be brought back to the body. Unfortunately, we are not spiritually sensitive to ascertain the truth of the information. We are unable to sift out the grain from the chaff. Joseph, on the other hand, had a special quality that allowed him to do this sifting. What was that special quality?
Another kabbalist adds an insight that completes the puzzle.
“The one who is able to discern the content of the imagination is someone who is free from physical desire like Joseph, who conquered the desire for women, and Daniel, who conquered the desire for food. They could interpret dreams. This because the root of all the thoughts we have is in our desires. They cause the mind to imagine. Someone absorbed by thoughts controlled by desire, can’t pull out the kernel of truth enclothed in those thoughts.” 
The pureness of the heart controls the ability to discern the spiritual information in dreams. Dreams are therefore connected to three main aspects of spirituality. First, our dreams are an avenue for communicating with the Almighty. As our tradition states that the era of prophecy has ended, this first aspect is purely educational. Secondly, that a dream is a conduit for information about the future. This will be of use to you if you are sensitive to spirituality, and pure of heart. The last aspect is practical and useful for us all, that dreams are a window to your inner desires. The imagery is there to let you know which desires linger in your heart. These desires need to be conquered in order to move up to the next level of closeness to your Creator.
Take note of your dreams, they reveal your challenges. Rabbi Moshe Chaim Luzzatto, The Way of God, III:1:6  Tzidkas HaTzaddik, Section Seven, Note 203