Abraham Lincoln was fond of asking, "If you call a dog's tail a leg, how many legs does a dog have?" "Five," his audience would invariably answer. "No," he'd politely respond, "the correct answer is four. Calling a tail a leg does not make it a leg."
Like Lincoln's associates, many of our fellow citizens—including many Christians—appear to fall for the notion that changing a definition causes a change in essence. A prime example is the attempt to change the definition of marriage to include same-sex unions. Simply calling such relationships "gay marriages," many believe, will actually make them marriages. Such reasoning, however, is as flawed as thinking that changing tail to leg changes the function of the appendage.
Consider the change that must occur in our tail/leg example. A dog's tail cannot perform the same functions as its leg. He can't use his tail to run or swim or scratch an itch. In order to use the term for both parts, we must discard all qualities that make a tail different from a leg. The new meaning of leg will require that we exclude any difference of form (for example, we can no longer say that a paw can be found at the end of a leg) or function (for example, legs are not necessarily used for standing). In other words, by redefining the term tail we have not made it equivalent in form or function to a leg; we've merely stripped the term leg of its previous meaning and made it as generic a term as appendage.
The same is true with the attempts to redefine marriage. Because marriage requires the specific form of a union of man and woman (Gen. 2:24), applying the term to same-sex unions alters the very concept of what a marriage is for and what functions it takes.
For example, a significant percentage of people in same-sex sexual partnerships do not view monogamy or sexual exclusivity as part of the meaning of marriage. They may still use the term monogamy, but they have redefined that term too, in a way that means "monogamish," that is, relationships in which they are emotionally intimate with only one partner yet remain free to engage in sexual infidelities or group sexual activity. Changing the definition of marriage to include same-sex unions does not make it more inclusive, but rather more exclusive, since it requires excluding all the functions that were previously believed to be essential to the institution of marriage (for example, sexual fidelity).
Some Christians, recognizing the change that occurs because of the redefinition of marriage, argue that we need a two-track system: marriage as defined by the state and marriage as defined by the church. The problem with this view is that it also misunderstands the nature of marriage. Neither the state nor the church has the authority to change the essential nature of marriage, since the institution was neither created by nor belongs to either the church or the state. As Dr. R.C. Sproul wrote in a previous issue of Tabletalk (June 2013):
Marriage is ordained and instituted by God—that is to say, marriage did not just spring up arbitrarily out of social conventions or human taboos. Marriage was not invented by men but by God.
Because the three institutions of church, state, and marriage have interdependent yet independent existence, they can decide whether to recognize each other's legitimacy, but they cannot delineate each other's boundaries. In this way, the relationship is similar to nation-states. The U.S. government, for example, can decide to "recognize" the state of Israel, but it cannot redefine the country in a way that contracts its border to exclude the Gaza Strip. The U.S. either recognizes Israel as it defines itself or it rejects its legitimacy altogether.
Some Christians may even concede that while the state doesn't truly have the authority to redefine marriage, we should go along with the legal fiction for the sake of the gospel witness. Although such Christians may have the best of intentions, they are actually subverting the very gospel they want to protect.
In acceding to laws that redefine marriage, they are doing the very opposite of what Jesus calls us to do: they are hating their neighbors, including their gay and lesbian neighbors. You do not love your neighbor by encouraging them to engage in actions that invoke God's wrath (Ps. 5:4–5; Rom. 1:18). As Christians, we may be required to tolerate ungodly behavior, but the moment we begin to endorse it, we too become suppressors of the truth. You cannot love your neighbor and want to see them excluded from the kingdom of Christ (Eph. 5:5).
What is needed is for the church to have the courage to speak the truth of the gospel: we cannot love our neighbor and tolerate unrepentant rebellion against God. We cannot continue with the "go along to get along" mentality that is leading those we love to destruction. We must speak the Word of God with boldness (Acts 4:31) and accept the fact that those who have fallen away may not ever return. We must choose this day whom we will serve. Will we stand with the only wise God or with the foolish idol-makers of same-sex marriage?