All the men of Israel, when they saw the man, fled from him and were much afraid. And the men of Israel said, “Have you seen this man who has come up? Surely he has come up to defy Israel. And the king will enrich the man who kills him with great riches and will give him his daughter and make his father's house free in Israel.” And David said to the men who stood by him, “What shall be done for the man who kills this Philistine and takes away the reproach from Israel? For who is this uncircumcised Philistine, that he should defy the armies of the living God?” And the people answered him in the same way, “So shall it be done to the man who kills him.” (1 Samuel 17:24-27)
So, the man who kills Goliath will get three things from the king:
b. the king's daughter
c. freedom within Israel
When we put our penitent faith in Christ we get
a. riches. This is not material prosperity in this life. In fact, one has a better chance of getting true riches through material poverty. But mainly, we are talking about spiritual riches that are only found in Christ. 2 Corinthians 8:9 reads, "For you know the grace of our Lord Jesus Christ, that though he was rich, yet for your sake he became poor, so that you by his poverty might become rich." Paul is not talking about material riches. See what he says about Jesus himself in Philippians 2:
Jesus, who, though he was in the form of God, did not count equality with God a thing to be grasped, but emptied himself, by taking the form of a servant, being born in the likeness of men. And being found in human form, he humbled himself by becoming obedient to the point of death, even death on a cross. Therefore God has highly exalted him and bestowed on him the name that is above every name, so that at the name of Jesus every knee should bow, in heaven and on earth and under the earth, and every tongue confess that Jesus Christ is Lord, to the glory of God the Father. (Philippians 2:6-11)
Jesus gave up heavenly riches to impoverish himself on our behalf on earth. Now he is exalted with heavenly riches, so that we might, too, be exalted with heavenly riches. In the Sermon on the Mount, Jesus tells his disciples
“Do not lay up for yourselves treasures on earth, where moth and rust destroy and where thieves break in and steal, but lay up for yourselves treasures in heaven, where neither moth nor rust destroys and where thieves do not break in and steal. For where your treasure is, there your heart will be also." (Matthew 6:19-21)
Our heavenly treasure is Jesus himself.
b. The king's daughter. This doesn't mean that God gives us a new spouse in heaven. It doesn't mean we get "72 virgins." This means that we become part of the church, which is the bride of Christ. Remember, David, the victor of Goliath, is a type and shadow of Jesus, the victor over Satan. Jesus gets the king's daughter, which is the church, to be his bride. Ephesians 5:25 reads, "Christ loved the church and gave himself up for her, that he might sanctify her, having cleansed her by the washing of water with the word." When we put our faith in Christ, we are putting our faith in his word, and we seal this faith with our baptism.
c. Freedom. This is one of the most misunderstood aspects of Christianity on the part of the world. The world believes that by becoming part of a religion, we lose our freedom, because now we have to obey some set of arbitrary rules. Luther and the other reformers demonstrated that this wasn't so. Because of sin, we are incapable of choosing "the good." We choose selfishly, and if that decision happens to be a good one, and we help others through that decision, it is still a sinful and bad decision in God's eyes, because we were doing it for ourselves, not because we truly loved God or our neighbors. It's like staying in a relationship only because it makes you feel good. Once the feeling goes, and you're not enjoying yourself, we find it easy to break off the relationship. This is what sin does to us, and we are incapable of choosing the good for God's sake and our neighbor's sake. We are incapable of loving our neighbor as ourselves. This is slavery, not freedom.
But Jesus sets us free. Faith in Christ's blood gives us the freedom to choose the good, to love our neighbor as ourselves, many times at the expense of our own happiness and enjoyment. As Jesus says in John 8:31-32, "If you abide in my word, you are truly my disciples, and you will know the truth, and the truth will set you free." This connects freedom with being the bride of Christ. We are washed with the word, cleansed, and when we abide in this same word, we are truly Christ's disciples, the church, and we will know the truth and with that truth comes freedom, the freedom for do good works, which God as given us to do.
All three of these kingly rewards are found in Christ. Jesus does the work, the heavy lifting. He defeats Goliath for us. He gets the riches, bride, and freedom. It is our faith in Christ that puts us IN CHRIST, and so we get those rewards, too, through faith. We get heavenly riches through Christ. We become the bride of Christ and are cleansed through Christ. And we have real freedom in Christ, who is the way, the truth, and the life.