What does Judges 17:4 mean?

Micah's mother has shown mercy and forgiveness to her son (Judges 17:1–3). Instead of punishing him further for stealing a huge sum of money from her, she has proclaimed a blessing on him. She offered this "by Yahweh"—supposedly, in the name of the God of Israel—to replace the curse she uttered against the thief. She then proclaimed that the silver was to be dedicated to the Lord.

Rather than stopping there, she demonstrated the problem with Israel's worship during her era. She gives a portion of the silver to an artist, who creates at least one idol from it. The phrasing "a carved image and a metal image" could mean two separate objects, or a sculpture overlaid with a thin layer of precious metals. It's most likely two items, given later descriptions of Micah's shrine (Judges 18:17–18). Using this precise set of words seems like a direct reference to Deuteronomy 27:15 which explicitly condemns those exact things. Whether one item or two, the product of the artist's work is placed in Micah's house, along with other supposedly sacred objects.

It's difficult to imagine how a faithful Israelite could think it was reasonable to make carved idols as part of their worship when God had clearly told them not to do this (Exodus 20:3–5). This is part of the lesson of the last chapters of the book of Judges: the people were either ignorant of God's commands or didn't think they mattered. Instead, they made their own rules for spirituality. These fit more comfortably and easily into their times and culture.