Dreams allow awareness from somewhere other than the conscious mind to enter into our range of perspective without the prejudicial judgment of ego blocking the potential of larger reality. More directly, the best time for the divine to reach humanity is when we're not so busy being ourselves.
Judeo-Christian, Tao, Islam and Hindu religions all have significant appreciation for the dream as divine reality penetrating the consciousness of humanity. However, ideas about divine figures taking initiative in relationship with humanity vary widely within world religions.
What can be said here is that dreams that seem to include revelation from beyond could be treated as divine revelation itself, or as some sort of revelation from your own deepest values. In other words, don't be too concerned with the media through which any powerful message comes, or don't overanalyze the messenger. Let the message be the medium.