A Commentary, Critical, Practical, and Explanatory on the Old and New Testaments, by Robert Jamieson, A.R. Fausset and David Brown  at sacred-texts.com
1 Kings (1 Samuel) 5:1
sa1 5:1THE PHILISTINES BRING THE ARK INTO THE HOUSE OF DAGON. (Sa1 5:1-2)
Ashdod--or Azotus, one of the five Philistine satrapies, and a place of great strength. It was an inland town, thirty-four miles north of Gaza, now called Esdud.
1 Kings (1 Samuel) 5:2
sa1 5:2the house of Dagon--Stately temples were erected in honor of this idol, which was the principal deity of the Philistines, but whose worship extended over all Syria, as well as Mesopotamia and Chaldea; its name being found among the Assyrian gods on the cuneiform inscriptions [RAWLINSON]. It was represented under a monstrous combination of a human head, breast, and arms, joined to the belly and tail of a fish. The captured ark was placed in the temple of Dagon, right before this image of the idol.
1 Kings (1 Samuel) 5:3
sa1 5:3DAGON FALLS DOWN. (Sa1 5:3-5)
they of Ashdod arose early--They were filled with consternation when they found the object of their stupid veneration prostrate before the symbol of the divine presence. Though set up, it fell again, and lay in a state of complete mutilation; its head and arms, severed from the trunk, were lying in distant and separate places, as if violently cast off, and only the fishy part remained. The degradation of their idol, though concealed by the priests on the former occasion, was now more manifest and infamous. It lay in the attitude of a vanquished enemy and a suppliant, and this picture of humiliation significantly declared the superiority of the God of Israel.
1 Kings (1 Samuel) 5:5
sa1 5:5Therefore neither the priests . . . nor any . . . tread on the threshold of Dagon--A superstitious ceremony crept in, and in the providence of God was continued, by which the Philistines contributed to publish this proof of the helplessness of their god.
unto this day--The usage continued in practice at the time when this history was written--probably in the later years of Samuel's life.
1 Kings (1 Samuel) 5:6
sa1 5:6THE PHILISTINES ARE SMITTEN WITH EMERODS. (Sa1 5:6-12)
the hand of the Lord was heavy upon them of Ashdod--The presumption of the Ashdodites was punished by a severe judgment that overtook them in the form of a pestilence.
smote them with emerods--bleeding piles, hemorrhoids (Psa 78:66), in a very aggravated form. As the heathens generally regarded diseases affecting the secret parts of the body as punishments from the gods for trespasses committed against themselves, the Ashdodites would be the more ready to look upon the prevailing epidemic as demonstrating the anger of God, already shown against their idol.
1 Kings (1 Samuel) 5:7
sa1 5:7the ark of God shall not abide with us--It was removed successively to several of the large towns of the country, but the same pestilence broke out in every place and raged so fiercely and fatally that the authorities were forced to send the ark back into the land of Israel [Sa1 5:8-10].
1 Kings (1 Samuel) 5:11
sa1 5:11they sent--that is, the magistrates of Ekron.
1 Kings (1 Samuel) 5:12
sa1 5:12the cry of the city went up to heaven--The disease is attended with acute pain, and it is far from being a rare phenomenon in the Philistian plain [VAN DE VELDE].