I think that the main message of Whitman's poem in Leaves of Grass was to bring out the awesome force of the natural setting in the midst of human imagination. The setting of the speaker, presumably Whitman, walking along the edge of a beach, looking out at the night and the water in front of him, is overwhelming. This sense of the awesome is brought out in the poem. The natural condition in the poem is alive and vibrant, reflected in verbs such as "careening," or "the winds breasting." These elements help to evoke an idea that there is a natural condition alive and vibrant, almost dwarfing the viewer of such a scene. The storm that opens the poem and its presence at the end of it is meant to keep relegate the individual into a position to recognize their own subservient condition to the realities of the natural setting. It is in this where I think that the main message of the poem is illuminated. When left to a setting in which individuals can see things as they truly are, there is a reality in which human beings can uses their own powers of sensation to understand that the true configuration of reality is one in which the awesome powers of nature must be respected and revered.