Daniel for the record I agree with the Legalist's premise as far as the New Covenant being a type of contract.
Very few have a grasp of both theology and law, and I disagree with the author of your article. Of course since he was raised in the Netherlands and his only degree as far as I can tell was in theology, and perhaps they have a different understanding of contract law than American Jurisprudence does.
As for the
berith- even in contract law there is such a thing as a unilateral contract.
The old testament was just that, a legally binding agreement between God and man which went into effect at the death of the testator.
The New Covenant- (which I prefer to Testament, because there will be only one death) began with the fulfillment of that "old" testament.
So as far as principle, I would agree with the Legalist.
Now application is a different matter. I cannot see where
Romans 6 ties into that per se.
A condition precedent? I find that a stretch.