The light came through the window
Straight from the sun above
And so inside my little room
There plunged the rays of love
In streams of light I clearly saw
The dust you seldom see
In various songs Cohen sings of a cell-like little rooms (like in monasteries) where the speaker and sometimes other characters live in: 
 “I’ve lain by this window long enough To get used to an empty room” (Master Song) 
 “I choose the rooms that I live in with care The windows are small and the walls almost bare There’s only one bed and there’s only one prayer” (Tonight Will Be Fine) 
 “And the last time that I saw her she was living with some boy Who gives her soul an empty room and gives her body joy” (Death of a Ladies' Man) 
 “I told my mother "Mother I must leave you Preserve my room but do not shed a tear” (The Traitor) 
 Cohen himself lived several years in a Buddhist retreat, becoming a monk, and this song seems like a mystical experience he reached in loneliness and meditation.
Love Itself