John Gill Commentary Judges 18:27

"And they took that which Micah had made, and the priest whom he had, and came unto Laish, unto a people quiet and secure, and smote them with the edge of the sword; and they burnt the city with fire." — Judges 18:27 (ASV)

And they took the things which Micah had made
The ephod, teraphim, and the two images, the Danites took them, or having taken them kept them, and went on with them:

and the priest which he had ;
him also they took, and who was willing enough to go with them:

and came unto Laish, unto a people that were quiet and secure ;
having no sentinels placed at any distance to give them warning of an enemy, nor any watchmen on their walls to discover one; and perhaps their gates not shut, nor any guard at any of their passes and avenues, having no apprehension at all of being visited by an enemy, especially from Israel, not being apprized that they had any pretensions to their city, and the land about it:

and they smote them with the edge of the sword ;
entered their city, and fell on them suddenly, and cut them to pieces:

and burnt the city with fire ;
to strike terror to all about; or it may be only they set fire to some part of it, as they entered, only to frighten the inhabitants, and throw them into the greater confusion, that they might become a more easy prey to them; for their intention was to inhabit it, and it seems to be the same city still, though they rebuilt it, and called it by another name.