Hard to find a better example of this antithetical view of Law/Gospel than this from Scott Clark:
"The Law and the Gospel are necessarily dichotomous since the former only condemns and the {latter} only justifies"
That is a good example. Especially considering that it is in the context of the doctrine of justification. What Reformed theologian denies this antithetical relation in regards to justification?
However, if the example was given as a way to discredit his view of sanctification, then the rest of the context in which this example is given is most helpful:
Westminster Seminary California
Three things of notice:
1. the law and gospel are opposed to one another at the point of justification. The law does not justify.
2. isolating one statement out of a systematic theology context is a disservice to one's entire thought
3. the law is affirmed as in harmony with gospel later on in point 22 of section 8, among many other theses to the same, especially point 39 of section 5 (just 3 points after the given example)
I appreciate the attempt to make sense of his theological propositions, but the quote I highlighted says the law "only" condemns. "Only" does not permit exceptions, nor does that statement give any. While he goes on to affirm the 3rd use of the law, {of course he must}, he has no stable theological basis to do so.