This is one of the greatest songs of all time.  That is objective fact.  This song is also a great embodiment of Jamaican reggae.  It has a very laid back feel, with emphasized bass and a strong 2 4 back beat.  The song is about the struggle and life of African peoples in the Americas, as they are “fighting on arrival, fighting for survival.”  Bob Marley was one of the great pioneers of modern reggae, and a great component in bringing it into the mainstream of American music.