John Calvin on James 2:11

11 For he that said, or he who hath said. This is a proof of the former verse; because the Lawgiver is to be considered rather than each particular precept apart. The righteousness of God, as an indivisible body, is contained in the law. Whosoever, then, transgresses one article of the Law, destroys, as far as he can, the righteousness of God. Besides, as in one part, so in every part, God’s will is to try our obedience. Hence a transgressor of the law is every one who offends as to any one of its commandments according to this saying,

“Cursed is he who fulfills not all things.” (Deuteronomy 27:26.)

We further see, that the transgressor of the law, and the guilty of all, mean the same according to James.

James 2:12-13

12 So speak ye, and so do, as they that shall be judged by the law of liberty.

12 Sic loquimini, et sic facite, ut per legem libertatis judicandi.

13 For he shall have judgment without mercy, that hath shewed no mercy; and mercy rejoiceth against judgment.

13 Judicium enim sine misericordia ei qui non praestiterit misericordiam; et gloriatur misericordia adversus judicium.