The Tragedy of Julius Caesar was portrayed by Shakespeare since he was inspired by ancient kingdoms and empires to write his plays.
In Act 5, Scene 2 of Julius Caesar, Brutus instruct Messala to defeat the enemy's army assuming Octavius' side would be easy to overcome after putting pressure on it.
Thereby, "The urgent tone would be softened considerably" if the phrase were changed to "advance", since it would allow the enemy to gain the confidence they were lacking at that very moment.