Image of God is forbade

Judges 8:22-35
It is good that Gideon told them, “I will not rule over you, nor will my son rule over you. The Lord will rule over you.”
It is wrong that Gideon told them "each of you give me an earring from your share of the plunder." Gideon made the gold into an ephod, which he placed in Ophrah, his town. All Israel prostituted themselves by worshiping it there, and it became a snare to Gideon and his family.
Ephod: In the Old Testament, the ephod has two meanings. In one group of passages, it signifies a garment; in another, very probably an image. As a garment the ephod is referred to in the priestly ordinances as a part of the official dress of the high priest.
The word ephod has an entirely different meaning in the second group of passages. The most natural inference from all these passages is that “ephod” here signifies an image that was set up in the sanctuary, especially since the word is cited with teraphim, which undoubtedly refers to graven(雕像) images. ephod, in these cases, refers to a portable idol.
On the death of Gideon, the Israelite once again began to worship the Baals. God was fine in a crisis, but when that was forgotten the pull of gods who would bind Israel to their neighbours and give good crops was too strong.
Why?
Probably an image of God, which the law forbade, though Good News Bible translates 'idol'. The place then became a rival to Israels official sanctuary.
People always easy to forget the sad consequence for their sins after they have peace.
How?
Carefully to follow God's word and commandment, even Gideon took great things but he failed in his way at last.