Quote by Herodotus, Histories
These 'messengers' will not be hindered from accomplishing at their best speed the distance which they have to go, either by snow, or rain, or heat, or by the darkness of night.
Summary
This quote suggests that the messengers referred to in the statement will not let any obstacles stand in their way as they strive to complete their journey swiftly. Whether it be snow, rain, heat, or even the darkness of night, they will remain undeterred and continue to persevere. It portrays the messengers as determined and committed individuals who are capable of circumventing any challenges that may arise during their mission.