Wintley Phipps is an incredible singer and featured soloist who shares some really inspirational information during this clip while doing a concert. The pentatonic scale is made up of only the black keys. The African slaves were known for singin in this scale chord progression. All of the black spirituals had this same melodic tone. Try it, go play the black keys on a piano and you will hear many old spirituals sung in that key. He goes on to share the orientation of the song, Amazing Grace. See the writer of the lyrics to the song Amazing Grace was John Newton and he was a slave ship captain before he came to Christ. He heard the melody to this most famous spiritual while taking peole captive as they sang in captivity in the bowels of the ship. Later in life, John Newton, penned the words to Amazing Grace to this African song he had heard years before. If you haven't seen the movie, Amazing Grace...I highly recommend it!