Hi there!
Grove has told the engineers "the only thing we have to think about is that the war is over" because the decision to use atomic weapons was opposed by some who felt it was immoral.
That excerpt is from the speech given in 1945, to engineers on the Manhattan Project by the military commander in charge of the Manhattan Project, General Leslie Grove. In 1942, General L. Groves was appointed to head the Manhattan Project. He was in charge of all of the phases of the project. The phases included scientific, technical and process development; construction; production; security and military intelligence of enemy activities; and planning for use of the bomb.
Hope this helps!