I was reading something the other day that mentioned President Obama's rendition of "Amazing Grace" at the 2015 memorial service for slain Charleston pastor and state senator Clementa Pinckney. Another article, in Atlantic, mentioned that he performed it distinctly in the style of the black church. This article (which includes a link to the entire two-plus-hour service honoring all the slain church members) speaks in depth about the thirteen-second pause that separated Obama's 35-minute eulogy, which was met with frequent call-and-response encouragement—amens and cheers—and his singing of this simple, beautiful song.
This extended silence is called the "sermon pause." "It is not a 'dead silence' but a 'live silence,' " writes the author of The Hum: Call and Response in African American Preaching. "It is a silence that organizes time, that invites us to think of time not as something passed but as something plotted."
In contrast to the boisterousness of the congregation to this point, during Obama's pause you could hear a pin drop: utter stillness and anticipation. Powerful and moving. Here it is: the pause and the song both.