Lyric discussion by Wescoh 

Cover art for Crisis lyrics by Bob Marley and the Wailers

The biggest clue is at the beginning where he states "in some peoples world it (the sun) never shines at all" This is true figuratively and literally. Could be depression, prison or some other reason, but it's true in this world. If you go from there the rest of the song is a lament to rise above your personal crisis if you can. Bob is a great lyricist.