The context for this story is the Israelite oppression under the Canaanites. The LORD "sold them" (4:2) into the hands of the king of Canaan because of the "evil" they did in the eyes of LORD. This evil occurred after the death of Ehud, which plays into the pattern created at least in the early part of Judges: the people commit evil before God; God turns them over to foreign rulers; they are oppressed and cry out for help; God hears their cries and sends a judge to deliver them; they have peace in their land; they turn back to evil after the judge dies.
As expected, because of their oppression, and apparently also because of Sisera's nine hundred iron-fitted chariots, the people cried out to the LORD for help.
God heard their cries and answered (all this is inferred) by speaking through Deborah to Barak. Deborah is not the judge or deliverer in this story. Nowhere is God described as "raising up" a judge (see 2:16; 3:9, 15). She was a prophet who was described as "leading" Israel at that time. Since she was leading while Israel was under oppression she probably acted more like a judge as we would understand one—she decided disputes among the Israelites.
Yet she also received the word from the Lord that called Barak to be a deliverer for God's people and she was tasked with the responsibility of passing this on to Barak. Barak will deliver God's people by defeating Sisera in battle. Specifically, God will "give" Sisera into Barak's hands.
Interestingly, it is Deborah calling all the shots in this story even though Barak was called as the deliverer: she calls him, she delivers the message to him that he will be God's deliverer, she tells him he won't get the glory (because of his hesitation), then she orders him to go to battle ("Go! This is the day the LORD has given Sisera into your hands!")
Deborah is a leader. Even though she is never labeled in Judges as the deliverer in this story, by functioning as a prophet who brought God's word and as a leader who called and empowered the deliverer (even though the glory went to someone else), she is the example of what it means to stand for God in chaotic times.
Barak is called by Deborah and told he will win the battle. We can assume he's some kind of military leader within Israel, or at least an experienced fighter, but for some reason he is reluctant to go into battle. He will go only if Deborah accompanies him.
Barak is often criticized because of this: he wasn't a real man, he wasn't committed to following God, etc. But what if we viewed Barak with a little less criticism? If someone delivered a message from God for and to you, wouldn't you feel better if that messenger of God accompanied you? Barak may have viewed Deborah as a good luck charm of sorts—God would be with him because God was with Deborah.
It may also be that he was unfaithful. But I wonder if, when we view him as unfaithful, we're reading ourselves into his story?
The real problem for Barak is that, inadvertently or not, his actions demonstrate that he does not fully trust God as God. The word of God is delivered to him but he wants the broker of God's word, the middle-woman, to accompany him, wrongly believing that the fulfillment of God's word (prophecy) will be delivered through the presence of Deborah, not on the strength of God's word itself. As a result, God will still deliver his people but Barak will not get the glory from this military victory.
The narrative of Judges is clear that even though Barak advances, it is God who does the work of routing Sisera's army (4:15). As a result of God's work, all of Sisera's fighters were killed. But Sisera was able to escape, which leads to the revealing of the real deliverer—the non-Israelite, Jael.
Here's what we learn from Barak: When we follow God, and specifically when we do what he calls us to do, he gives us all the resources we need to serve him. There's no magic charm, magic prayer, magic person, or even magic book that guarantees God's presence with us. His promise is all we need.
As Sisera escaped, the narrative focused on an alliance that had been made between the king of Canaan and the family of Heber. This was convenient for Sisera because it gave him an out—he could run for protection and run he did (he "fled on foot"; 4:15, 17). He made his way directly to Heber's house where he was met by Jael, Heber's wife. He demanded aid from Jael and appeared to receive it, although not in the form he demanded: when he asked for a drink of water to quench his thirst he was given milk, which made him sleepy. But before he fell asleep he made another demand of Jael: she was to keep watch for him and if anyone came by asking if a man was inside her tent, she was to tell them no.
Wait a minute—no man inside the tent? What did Sisera consider himself to be? While it's obvious he told Jael to say this for his protection, it is humorous (and a bit ironic) that he undermined his own manhood and "invincibility" by hiding under a rug and demanding Jael lie for him.
But the final irony came while he was asleep. Jael grabbed a tent peg and drove it through his skull, killing him. The she went out to meet Barak to turn over the dead Sisera.
This is intended to be both ironic and something that showed the glory of God--that God ensured his will was done despite the human alliances made by his enemies.
The hero of the story is Jael—an unlikely hero. This unlikely hero—a woman, a non-Israelite—did the work of God (4:23)! The true hero should have been Barak, or perhaps even Deborah, but it was a non-Israelite who served God in the unlikeliest of ways. This teaches us that no matter how small or insignificant we think we are, God can do great things through us if we are willing to follow him as he leads us. In fact, there is no "small" or "insignificant" with God—he is ready to use anyone who loves him, anyone who is ready to do his work. All you need to do is make yourself available to be led by God.
Jael was the hero in Judges 4, not Barak, because she acted in simple obedience out of her faith. Barak got hung up by a false view of God—he believed, idolatrously, that God's presence was available to him in the person of Deborah. And it cost him.
Here are four false views of God we have today in the church:
1. The "Santa Claus" god who exists to give us everything we want. This god hangs us up because if we don't get what we think we deserve, we start to question his goodness.
2. The "he-didn't-really-mean-what-he-said-he-just-wants-to-know-if-you-are-willing" god. This god offers hard teachings but doesn't really mean them. This god usually is behind the biblical teaching about money. When Jesus told a rich guy to go sell everything he had and then come follow him, he didn't really mean it, he just wanted to know if the man would be willing to do so. This view of god hangs up because it removes the hard questions of discipleship from our lives.
3. The "we're-right-and-no-one-else-is" god. This god allows us to feel prideful that we've read the Bible correctly and no one else has. This view of god also hangs us up because it gives us a false assurance that our faith is about knowledge of spiritual things, or activities at the church building, or having the correct forms of worship, rather than Jesus.
4. The god of tradition. This view of god is deadly because it keeps us rooted in the past rather than looking at how we should serve God in the present and in the future.
This is why Jesus contrasted tradition (and all false views of god) with true faith in the living God (Mark 7). He showed us that faith is internal belief and simple action that is driven by that faith.
This was exemplified by Jael, who knew what she needed to do for God and did it.