I subscribe to the view that the African slave work songs, "spirituals" are at the root of blues, gospel, jazz and influenced all black music of the 20th Century.
Wikpedia...."Spirituals (or Negro spirituals)[1][2] are generally Christian songs that were created by African Americans.[3] Spirituals were originally an oral tradition that imparted Christian values while also describing the hardships of slavery.[4]Although spirituals were originally unaccompanied monophonic (unison) songs, they are best known today in harmonized choral arrangements. "
I think it's hard to deny the Christian element in the evolution of soul music.