Albert Barnes Commentary 1 Samuel 4:6

"And when the Philistines heard the noise of the shout, they said, What meaneth the noise of this great shout in the camp of the Hebrews? And they understood that the ark of Jehovah was come into the camp." — 1 Samuel 4:6 (ASV)

Of the Hebrews - This was the name by which the Israelites were known to foreign nations (Exodus 2:6).