Could just be my conspiracy bone actin' up but, he could also simultaneously be giving a unique message to each office so as to know the source if any leaks occur.
I was rhink it was to motivate and "buck up" the ranks who will be carrying the biggest "sweep" in the Bureau's history. Think Eisenhower on the eve of D-Day.
Ladies and Gentlemen:
You are about to embark upon the Great Crusade, toward which we have striven these many months. The eyes of the world are upon you. The hope and prayers of liberty-loving people everywhere march with you. In company with our brave Allies and brothers-in-arms on other Fronts, you will bring about the destruction of the German war machine Deep State, the elimination of Nazi Clown tyranny over the oppressed all the peoples of Europe the world, and security for ourselves in a free world.