28 When the men of the town rose early in the morning, behold, the altar of Ba'al was broken down, and the Ashe'rah beside it was cut down, and the second bull was offered upon the altar which had been built. 29 And they said to one another, "Who has done this thing?" And after they had made search and inquired, they said, "Gideon the son of Jo'ash has done this thing." 30 Then the men of the town said to Jo'ash, "Bring out your son, that he may die, for he has pulled down the altar of Ba'al and cut down the Ashe'rah beside it." 31 But Jo'ash said to all who were arrayed against him, "Will you contend for Ba'al? Or will you defend his cause? Whoever contends for him shall be put to death by morning. If he is a god, let him contend for himself, because his altar has been pulled down." 32 Therefore on that day he was called Jerubba'al, that is to say, "Let Ba'al contend against him," because he pulled down his altar.
Matthew Henry's Commentary on Judges 6:28-32
Commentary on Judges 6:25-32
(Read Judges 6:25-32)
See the power of God's grace, that he could raise up a reformer; and the kindness of his grace, that he would raise up a deliverer, out of the family of a leader in idolatry. Gideon must not think it enough not to worship at that altar; he must throw it down, and offer sacrifice on another. It was needful he should make peace with God, before he made war on Midian. Till sin be pardoned through the great Sacrifice, no good is to be expected. God, who has all hearts in his hands, influenced Joash to appear for his son against the advocates for Baal, though he had joined formerly in the worship of Baal. Let us do our duty, and trust God with our safety. Here is a challenge to Baal, to do either good or evil; the result convinced his worshippers of their folly, in praying to one to help them that could not avenge himself.