God permitted His ark to be taken by their enemies, to show Israel how vain it was to trust in the ark, the symbol of His presence, while they were profaning the commandments contained in the ark. God would humble them by removing from them that sacred ark, their boasted strength and confidence. SR 187.3
The Philistines were triumphant, because they had, as they thought, the famous God of the Israelites, which had performed such wonders for them and had made them a terror to their enemies. They took the ark of God to Ashdod and set it in a splendid temple, made in honor to their most popular god Dagon, and placed it by the side of their god. In the morning the priests of these gods entered the temple, and they were terrified to find Dagon fallen upon his face to the ground before the ark of the Lord. They raised Dagon and placed him in his former position. They thought he might have fallen accidentally. But the next morning they found him fallen as before, upon his face to the ground, and the head of Dagon and both his hands were cut off. SR 188.1
The angels of God, who ever accompanied the ark, prostrated the senseless idol god and afterward mutilated it, to show that God, the living God, was above all gods, and that before Him every heathen god was as nothing. The heathen possessed great reverence for their god, Dagon; and when they found it ruinously mutilated and lying upon its face before the ark of God, they were sad and considered it a very bad omen to the Philistines. It was interpreted by them that the Philistines and all their gods would yet be subdued and destroyed by the Hebrews, and the Hebrews’ God would be greater and more powerful than all gods. They removed the ark of God from their idol temple and placed it by itself. SR 188.2
The ark of God was kept seven months by the Philistines. They had overcome the Israelites and had taken the ark of God, wherein they supposed their power consisted, and thought that they should ever be in safety and have no more fear of the armies of Israel. But in the midst of their joy at their success a wailing was heard all over the land, and the cause was at length credited to the ark of God. It was borne from place to place in terror, and destruction from God followed its course, until the Philistines were greatly perplexed to know what to do with it. Angels, who accompanied it, guarded it from all harm. And the Philistines did not dare to open the chest; for their God Dagon had met with such a fate that they feared to touch it, or to have it near them. They called for the priests and the diviners, and inquired of them what they should do with the ark of God. They advised them to send it back to the people to whom it belonged, and to send with it a costly trespass offering, which if God would be pleased to accept, they would be healed. They should also understand that God's hand was upon them because they had taken His ark, which belonged alone to Israel. SR 188.3