This verse discusses a very familiar piece of equipment in ancient commerce – the balance scale. It was typically constructed with two pans attached to an overhead beam which was, itself, fixed on a vertical center post. Product was typically weighed in one pan with the “official” weight-stone in the other.
There are a number of verses in Proverbs which discuss dishonest weights or scales (11:1; 16:11; 20:23). Our verse notes “differing weights” (literally “stone and stone”) and “differing measures” (literally “epah and epah”).
The fact that they’re doubled or compared, seems to suggest a problem. That “the LORD detests them both” makes it clear that there’s a serious problem!
While those two “stones” should have been identical, some ancient merchants had a buying weight-stone (heavier) and a selling weight-stone (lighter) – and the same with the “epah” measure.
Admittedly, it is God who we ultimately sin against. But the message here is about dishonest dealings with each other – and God hates it when we do that!