The priest's heart was glad; being wholly governed by his own interest, and making all his obligations of justice and gratitude give place to it. But it is not strange, if he who was before perfidious to God, should prove so to men. In the midst of the people, i.e. among the people; or properly in the midst, both for the greater security of such precious things, and that Micah might not be able to come at him, either to injure or upbraid him; and it may be, because that was the place where the ark used to be carried.
Related Commentaries of Judges 18:20
Judges 18:20
20 And the priest's heart was glad, and he took the ephod, and the teraphim, and the graven image, and went in the midst of the people.