There are two aspects of prayer. One is supplication asking for something and the other is worship acknowledging the supremacy of the Ultimate. Psychologically, the human being has always needed to feel that there is a greater power than himself available to him. To be praying in a dream reinforces this, since we need to use our own inner sense of self to access the Greater Power. Prayer suggests the idea that we need to seek outside help for ourselves. We may need someone else's authority to succeed in what we are doing. It also can indicate our ability to draw on our own inner resources. You might also like to consult the entry for Spiritual Imagery in the Introduction.