Yet, without waffling in the slightest on the above declaration, I don't believe the state should legislate against homosexuality. In other words, I am against sodomy laws and if I had been on the Supreme Court in 2003 when Lawrence vs. Texas was argued, I would have voted to repeal the sodomy laws too. Is that an inconsistency? To some, maybe; especially to those who believe we should Christianize the nation, or return it to its (questionable) Christian roots.I affirm, with Calvin and the Reformed confessions, that the Law has three uses (or offices): 1) to convict of sin, 2) to restrain wickedness, even in the unconverted, 3) to be our guide to holiness. Some might pick up on the second office and ask, 'shouldn't we implement anti-sodomy laws to restrain the wickedness of homosexuality?' The answer, I think, is 'No'.
Is homosexual activity a violation of God's law. Unequivocally, yes. One could point to many such precepts in the Old Testament, along with similar condemnations in the New. I think it is enough to say it is a violation of the seventh commandment, 'Do Not Commit Adultery'.
Still, we do not legislate obedience to all the ten commandments, nor could we. How will we legislate against covetousness? Some, I'm sure, would argue that homosexuality activity does not fall into the same category of covetousness, but more in the category of murder, theft, and the like since it isn't just an attitude, but an action. I see that distinction, but we don't legislate against premarital sex, which is an action also in violation of the seventh commandment. Nor do we legislate against idolatry, or making images of God, or dishonoring your parents, etc.
Going beyond that, some could truly argue that marriage isn't just prescribed in the written law and special revelation, but in creation itself. It is a statute written in natural law and codified more explicitly in the written code. Agreed. That is why, while I oppose sodomy laws, I am equally opposed to legalizing gay marriage (though I wouldn't want to see the church spearheading Prop 8's in every state - but that is a totally different conversation). I will take up that issue in a later post.
The sin of homosexuality is a serious one (what sin isn't; but, biblically speaking, not all sins are equally serious as shown by varying degrees of temporal punishment doled out), and one that churches should deal with appropriately. The grace filled mechanism of church discipline should be brought to bear on those actively living a homosexual lifestyle, just like it should be brought to bear on a heterosexual couple living together outside of wedlock.
Seems like a weird blending of tolerance and intolerance doesn't it. It is, but I think that is exactly what is needed. J. Gresham Machen, a hero of mine, argued for a widely open and tolerant society, provided that voluntary institutions like the church were permitted to be closed and intolerant. Quoting from DG Hart's summary of Machen's thought, "The reason why confessionalists like himself, he argued, were not flagrantly guilty of intolerance [towards the liberals of the day] was because involuntary organizations 'ought to be tolerant;, but voluntary ones 'so far as the fundamental purpose of their existence is concerned, must be intolerant or else they cease to exist.'" This led Machen, the arch-fundamentalist, to oppose prayer in public schools! That's right, he opposed it. He saw public schools as involuntary institutions, which they are (hence the term 'compulsory education') and therefore argued they should be open and tolerant of those who didn't believe in God or worshipped another god (in addition, he argued he wouldn't want his children, though he had none, to be taught prayer by someone of a different confessional stripe). The church, however, was completely different. The state was to support the right of the church to be intolerant - both of what it deemed wrong belief [the liberals] and, I think he would argue today, wrong action [like homosexuality].
Again, it's a delicate blending of tolerance and intolerance. In other words, what's good for the goose, and by goose I mean the church, isn't always good for the gander, referring to the culture at large. While it is our obligation to strive for a pure church, recognizing of course that absolute purity will only be achieved when Christ returns, it is not our biblical mandate, in the pluralistic state in which we live, to Christianize it or even Judeo-Christianize it (which seems to be the most we could hope for this side of Christ's return).
Here's a lecture by Dr. David Jones, Ethics professor at Covenant Theological Seminary I found helpful: pdf of transcript, mp3 of lecture.
(2011) is in many ways a companion to 
(2006), though the most recent publication is more focused and less technical.