Their actual first lines spoken in the comic.
I knew both scenes by heart, that it was grim and meant to impact and convey a strong bond, which it certainly does. But never realized these were both their actual first words ever spoken in the comics.
Neither has any dialogue before this.
Young Bruce Wayne:
Detective #33
Dick Grayson:
Detective #38
Yes adult Wayne is "Well, Commissioner, anything exiting happening these days?