A Christian wedding is a testimony, and all the guests are present at the wedding so that they might testify to the reality of that testimony. So that we might all understand our roles a bit better, a few comments are offered here as a reminder.

The first testimony is given by God Himself, and this testimony has various strands, at least three of them.
First, He testifies that mankind indeed is created in the image of God. God created us in His image, and the signature feature of that painting was with the flourish of “male and female,“ as He says in Genesis 1:27-28. And Jesus teaches us that when a man and woman are joined together, God is the one who is doing the joining. As He does this, He is continuing the glorious work of displaying His image.
The second point of God’s testimony can be seen in how God laid a heavy burden on our first parents after they sinned against Him by eating the forbidden fruit. His assigned chastisements were broken out by sex. For Adam, the ground was cursed and was going to bear fruit far more reluctantly than before. For Eve, the process of child-bearing was made that much more difficult. In the fall, the whole world fell, but the effects of that fall landed on men and women differently. So whenever a man and a woman come together in marriage, they are forming a union in order to confront this hard testimony of the Lord together. They do this by believing that testimony together, and by each sympathizing with the challenges faced by the other . . . instead of selfishly retreating into self-pity. We are to sympathize with the burden of the other, not compete with it.
The third testimony that God provides is the testimony of the gospel. After we sinned against Him, God did not leave us in that plight, but rather promised us a savior. The seed of the woman would come and crush the head of the seed of the serpent (Gen. 3:15). This promise was fulfilled in the death, burial and resurrection of Jesus Christ. But God did more than provide us with this gospel, thus giving us a message to declare and to preach. He also gave us embodied pictures of this gospel. One of them is of course the Lord’s Supper. As often as we eat the bread and drink the wine, we declare the Lord’s death until He comes.
But the other great picture of the gospel is that of Christian marriage—the picture that we have before us here today. Husbands, love your wives as Christ loved the church, and gave Himself up for her. That astonishing self-gift on the cross is the very center of the gospel, and the calling of the husband is to imitate the Lord ‘s death as a life-long pattern.
And the wife is to respond to her husband with respect and honor, imitating the church’s responsiveness to the offer of the gospel. The whole thing, done with wisdom and in the right spirit, is glorious.
As marriage and family are a direct institution of God, this means that He sets the parameters for it. He established it directly, and so He writes the by-laws. There are lesser governments that we create—a chess club or a book group—and so we have the authority to arrange the by-laws however we like. But marriage? No, not with marriage. God insists that we structure our marriages in a way that declares the gospel.
Now of course, because we are sinners, there are many who refuse to do this. But because of how God has embedded these realities in the very structure of marriage, this means that such people are doing much worse than simply behaving badly. They are also false teachers, lying about the gospel . . . which is a really bad thing to lie about.
You guests are all here as witnesses. In the light of the testimony God has given, and with that testimony having been clearly explained, this man and this woman are about to take solemn vows, in the sight of God, and in the presence of you, the assembled witnesses. You are not *simply* guests, but you also hold a very important office. You are here as representatives, representing all of society, the society within which Seth and Lilee will be establishing their household. You have heard God’s testimony. Hold it, and remember it.
Seth, you are assuming an office today, the office of husband. As mentioned earlier, you are charged with the task of loving this woman as Christ loved the church and gave Himself up for her. Because Christ is God, and because His death infallibly secured the salvation of all His elect, it is obvious that you cannot duplicate what He did. But whether you can duplicate it or not, you are still commanded to imitate it. In one sense, this is the only charge that needs to be given to you. Everything else you must do follows from this. I know you already feel this way in one sense, but add Christ’s example, and make the sense much fuller. This is a woman to die for.
Lilee, if he in a type is to be the death, you are (also in a type) to be a resurrection. Your task as a wife is to take everything he gives you, to glorify it, and then to return it to him—thirty, sixty, and a hundred fold. This is why Paul says that the man who loves his wife loves himself. Many men are daunted by the marital task that is set for them, and it is a challenging task. Your role is to beautify that daunting task for Seth, and make it totally worth it.
In the name of the Father, Son, and Holy Spirit, amen.