Charles Ellicott Commentary James 2:9

"but if ye have respect of persons, ye commit sin, being convicted by the law as transgressors." — James 2:9 (ASV)

But if you have respect to persons . . .—Translate, But if you respect persons, you work sin, and are convicted by the Law (i.e., at the bar of conscience) as transgressors. The first principle has been broken, and not a mere detail. De minimis non curat lex: the laws of men cannot concern themselves with trifles; but the most secret soul may be proven and revealed by some little act of love, or the contrary: and such is the way of the Lord that searcheth the hearts (Romans 8:27).