Histories
Herodotus
Herodotus. Godley, Alfred Denis, translator. Cambridge, MA; London: Harvard University Press; William Heinemann, Ltd., 1920-1925 (printing).
When he got there and came into Oroetes' presence, he took out each letter in turn and gave it to one of the royal scribes to read (all of the governors of the King have scribes); Bagaeus gave the letters to test the spearmen, whether they would consent to revolt against Oroetes.
Seeing that they were greatly affected by the rolls and yet more by what was written in them, he gave another, in which were these words: “Persians! King Darius forbids you to be Oroetes' guard.” Hearing this, they lowered their spears for him.