Albert Barnes Commentary 1 Samuel 4:12

"And there ran a man of Benjamin out of the army, and came to Shiloh the same day, with his clothes rent, and with earth upon his head." — 1 Samuel 4:12 (ASV)

Runners who were swift-footed and could travel long distances were important and well-known people (Compare to 2 Samuel 18:19–31). There always seem to have been professional runners who acted as messengers for armies in the field (2 Kings 11:4, 6, 19, where the King James Version translates the term as “guards”).

Earth upon his head - As a sign of bitter grief. See the related scripture references.