Then Phinehas stood up and intervened, and the plague was stayed.As will be shown, this is one of the most devastating verses for Sola Fide in the whole Bible. It's right up there along with James 2:24 and Romans 10:9-10 (see this article and this article). I personally believe it has more to offer than those other passages because it hits the Protestant where he least expects it.
And that was counted to him as righteousness [ἐλογίσθη αὐτῷ εἰς δικαιοσύνην] from generation to generation forever.
Most people have never seen Psalm 106:30-31, and the tiny minority of Protestants who do know about it keep it under tight wraps. Why? Because it targets one of their most "sacred" passages in Scripture, Romans 4:3-5 quoting Genesis 15:6 (Abraham believed God, and it was reckoned unto him for righteousness - ἐλογίσθη αὐτῷ εἰς δικαιοσύνην), and utterly demolishes their entire understanding of it. (In case you didn't notice, both verses use the identical Greek phrase for "credited as righteousness".)