Anons – John F. Kelly
offering hearts is meant to demonstrate that the soldiers are willing to give their bodies and lives to protect humanity and to ensure its survival
…members of the armed forces (and sometimes civilians in a show of respect towards military) salute by bending their arms and placing their clenched fist over their hearts. The gesture, known as "offering hearts" is meant to demonstrate that the soldiers are willing to give their bodies and lives to protect humanity and to ensure its survival. [Pic Related]
https://en.wikipedia.org/wiki/Salute#Clenched_fist_salute
[White House staff in observing a moment of silence on the south lawn of the White House at 8:37 A.M., the time the first tower was hit in the attacks of September 11, 2001]