From the recording Lucid Dreaming
Musically, this song is a meditation on an Amajor7 chord. The key of A, to me at least, is a bright and sunny tonal center. There is no distinct melody or rhythm (except for the beginning and end). The sound texture weaves a tapestry of "music sound"... it is not a song, but a musical environment or climate. Imagine yourself in a sunbeam, the light of God on your face. Be still and know.
"I will both lay down in peace, and sleep; For you alone, O Lord make me dwell in safety." (Psalm 4:8)