"Differing weights and differing measures, both of them are abominable to the Lord."
This in the Hebrew reads a stone and a stone. The idea is that one stone that looks like the same size is substituted so that a greater profit can be made. The stone was the weight which was the standard measure for market transactions. Some unscrupulous venders would have two different stones for each weight: one which was the standard weight and one which was lighter. If the lighter one was used, then the seller got the same price for less product. This was a way of deceiving the unwary buyer. Solomon is declaring God's opinion on this practice. God cares about whether you cheat people. Even if they will never know, God will know. You will know. You need to have the same prices and amounts for everyone and available to all. Even discounted prices need to be understood by all. If the price is subjective based upon the seller’s feelings or the buyer’s ability, then cheating is rampant.
God has a standard: Do unto others as you would have them do unto you. If you want to be treated a certain way, then treat other people that way – everyone.
This is the Hebrew phrase an ephah for an ephah. An ephah was a standard of measure. It was a certain amount of grain or crops. It was possible to cheat in this system by having a smaller ephah as the measuring stick or by saying something was an ephah, but it was not really.
Those who are believers in God must realize that He sees all transactions; and if you are knowingly cheating someone else to make a higher profit for yourself, He is displeased.
Do not be deceived, the New Testament declares, whatsoever a man sows that shall he also reap. If you cheat others, God will see to it that you are cheated either in this life or the one to come.
This is the Hebrew word toebah which means abomination, detestable, object of loathing.
It is important to realize that when the Scriptures tells us that God loathes something or finds it abominable, that means that it is contrary to His nature and being. The Old and New Testaments tell us about the God we serve who is the Almighty Supreme Being. They tell us that His standards are the standards for the whole world. What He, by His nature, says is not right or is not the way He created the world to be is abominable. When He declares, as the Creator and Lord of the Universe, that something is detestable, He means that it is against His nature and the nature of the way He made us and the world. It is not that it may not be enjoyable or profitable or interesting for a while, but it does not conform to His pattern. We need to be told these things because we, in our fallen condition, have a natural orientation toward selfishly enjoyable pursuits.
When God says to stay away from something, we should stay away from it, because He sees the unraveling that that action is causing. He sees the stream of negative consequences that those actions will bring about.
In this proverb, Solomon is saying that systematically cheating people to increase your profit is against the nature of our great and awesome God.
Isn't it great that we have the kind of God who finds this abominable? We do not serve a god who rejoices in treachery and illicit profit. However, there are some false gods that some people choose who embrace a “get as much as you can, any way you can” philosophy.