In Vergilium Commentarius
Maurus (Marius) Servius Honoratus
MOVENT IN PROELIA MARTEM nam moris fuerat indicto bello in Martis Sacrario ancilia commovere, unde est in octavo <3> utque inpulit arma.
THEY ROUSE MARS TO BATTLE: for it was the custom when war had been declared to move the Sacred Shields in the sanctuary of Mars, whence it is (written) in the eighth [book of the Aeneid] line three "he clashed his arms."
Translation by Jane W. Crawford, © 2001.