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
jdg 17:1MICAH RESTORING THE STOLEN MONEY TO HIS MOTHER, SHE MAKES IMAGES. (Jdg 17:1-4)
a man of mount Ephraim--that is, the mountainous parts of Ephraim. This and the other narratives that follow form a miscellaneous collection, or appendix to the Book of Judges. It belongs to a period when the Hebrew nation was in a greatly disordered and corrupt state. This episode of Micah is connected with Jdg 1:34. It relates to his foundation of a small sanctuary of his own--a miniature representation of the Shiloh tabernacle--which he stocked with images modelled probably in imitation of the ark and cherubim. Micah and his mother were sincere in their intention to honor God. But their faith was blended with a sad amount of ignorance and delusion. The divisive course they pursued, as well as the will-worship they practised, subjected the perpetrators to the penalty of death.
jdg 17:3a graven image and a molten image--The one carved from a block of wood or stone, to be plated over with silver; the other, a figure formed of the solid metal cast into a mould. It is observable, however, that only two hundred shekels were given to the founder. Probably the expense of making two such figures of silver, with their appurtenances (pedestals, bases, &c.), might easily cost, in those days, two hundred shekels, which (at 2 shillings, 4 pence each, is about 23 pounds) would be a sum not adequate to the formation of large statues [TAYLOR, Fragments].
jdg 17:5the man Micah had an house of gods--Hebrew, "a house of God"--a domestic chapel, a private religious establishment of his own.
an ephod--(see on Exo 28:6).
teraphim--tutelary gods of the household (see Gen 31:19 and see on Gen 31:26).
consecrated one of his sons who became his priest--The assumption of the priestly office by any one out of the family of Aaron was a direct violation of the divine law (Num 3:10; Num 16:17; Deu 21:5; Heb 5:4).
jdg 17:6every man did that which was right in his own eyes--From want of a settled government, there was no one to call him to account. No punishment followed any crime.
jdg 17:7Beth-lehem-judah--so called in contradistinction to a town of the same name in Zebulun (Jos 19:15).
of the family--that is, tribe.
of Judah--Men of the tribe of Levi might connect themselves, as Aaron did (Exo 6:23), by marriage with another tribe; and this young Levite belonged to the tribe of Judah, by his mother's side, which accounts for his being in Beth-lehem, not one of the Levitical cities.
jdg 17:8the man departed . . . to sojourn where he could find a place--A competent provision being secured for every member of the Levitical order, his wandering about showed him to have been a person of a roving disposition or unsettled habits. In the course of his journeying he came to the house of Micah, who, on learning what he was, engaged his permanent services.
jdg 17:10Micah said unto him, Dwell with me, and be unto me a father--a spiritual father, to conduct the religious services of my establishment. He was to receive, in addition to his board, a salary of ten shekels of silver, equal to 25 shillings a year.
a suit of apparel--not only dress for ordinary use, but vestments suitable for the discharge of his priestly functions.
jdg 17:12Micah consecrated the Levite--Hebrew, "filled his hand." This act of consecration was not less unlawful for Micah to perform than for this Levite to receive (see on Jdg 18:30).
jdg 17:13Now know I that the Lord will do me good--The removal of his son, followed by the installation of this Levite into the priestly office, seems to have satisfied his conscience, that by what he deemed the orderly ministrations of religion he would prosper. This expression of his hope evinces the united influence of ignorance and superstition.