Why describe the speed and motion of the enemy so intensely? Nahum wants us to understand that God's judgment, when it comes, is swift and unstoppable.
The repeated emphasis on movement – the whip urging on, wheels rattling, horses galloping, chariots bounding – highlights the unstoppable nature of the forces coming against Nineveh.
The Inevitable Onset
This isn't a slow, drawn-out siege. It's a swift, decisive onslaught. The sounds are not of hesitation but of determined, rapid advance. The original Hebrew uses strong, sharp sounds to mimic the actual noise, emphasizing the ferocity and speed of the attack.