The sight of the ephod and teraphim suggested the notion of inquiring of God.

Ask counsel - of God - As the Danites use the word אלהים Elohim here for God, we are necessarily led to believe that they meant the true God; especially as the Levite answers, Judges 18:6, Before the Lord (יהוה Yehovah) is your way. Though the former word may be sometimes applied to idols, whom their votaries clothed with the attributes of God; yet the latter is never applied but to the true God alone. As the Danites succeeded according to the oracle delivered by the Levite, it is a strong presumption that the worship established by Micah was not of an idolatrous kind. It is really begging the question to assert, as many commentators have done, that the answer was either a trick of the Levite, or suggested by the devil; and that the success of the Danites was merely accidental. This is taking the thing by the worst handle, to support an hypothesis, and to serve a system. See the end of the preceding chapter, Judges 17:13 (note).

And they said unto him, ask counsel, we pray thee, of God,.... They did not reprove him for assuming the priestly office, when they knew he was a Levite, such was the corruption of those times, and the great depravity and declensions they were fallen into; nor even for the idolatry he was guilty of, but encourage him in it, and thought they had got a fine opportunity, which they readily laid hold on, to have counsel asked for them of God, about the success of the errand they were sent about; to this they were led at sight of the ephod, which was like that in the tabernacle, and of the teraphim, images which, according to a notion that prevailed, when consulted, foretold future things; whether by God they meant the true God, who they thought would give an answer by these, or Micah's gods, is not certain; according to the Targum of Jonathan, they meant the true God, which paraphrases it,"ask of the Word of the Lord:"

that we may know whether our way which we go shall be prosperous or no; whether they should find out a proper place to dwell in, and be able to get possession of it.

And they said unto him, Ask counsel, we pray thee, of God, that we may know whether our way which we go shall be prosperous.

18:5 Ask - By thine Ephod, and Teraphim, or images, which they knew he had, ver.14.

17:7-13 Micah thought it was a sign of God's favour to him and his images, that a Levite should come to his door. Thus those who please themselves with their own delusions, if Providence unexpectedly bring any thing to their hands that further them in their evil way, are apt from thence to think that God is pleased with them.