Daily Zohar 3219
“בַּחֲלוֹם חֶזְיוֹן לַיְלָה בִּנְפֹל תַּרְדֵּמָה עַל אֲנָשִׁים בִּתְנוּמוֹת עֲלֵי מִשְׁכָּב.”
“In a dream, a vision of the night, When sound sleep falls on men, While they slumber in their beds,”
When people sleep, and the soul leaves the body, the Holy One Blessed be He, reveals the future to the people through the angel Gabriel. The dreams may have visions that come from a person’s heart. It means visions of truth, lies or a combination of both. The reason for revealing the future in dreams is for the person to awaken himself to follow the messages received on the path of correction.
The future of a person can not be revealed to the soul while it is in the body. The angel can only deliver the message to the soul is out of the body, in the spiritual realm without physical limitations. When the soul is back into the body, it can share the message with the cognitive functions of the brain.
There are many levels in dreams and in visions. Prophetic visions are above the levels of visions that are above the levels of dreams. (See also Zohar Vayetze #45, #50).
Our body is like a prison for the soul and limits its ability to communicate spiritually. If we close our eyes, we disconnect temporarily from some limitations and we can travel with our thoughts anywhere we wish. When we open our eyes, we are back to a limited and confined reality. The soul needs to leave the body for high-level spiritual communication. This is done during sleep outside the limits of the body and the influence of the senses that connect us strongly to this world. Highly spiritual people with proper meditations can separate their soul from the body and ascend to spiritual levels where they can see angels and visions. During the time of the Holy Temple, there were schools for prophets where they learn to meditate and ascend to levels of prophecy.
The dreams reveal true or false messages based on the spiritual level of the person. For similar reasons, most people forget their dreams or remember only parts of them.
A person may have several different dreams during sleep because the soul receives messages from the different levels it passes through on the way up or down.