James 2:8
If ye fulfil the royal law according to the scripture, Thou shalt love thy neighbour as thyself, ye do well:
Leviticus 19:18
Thou shalt not avenge, nor bear any grudge against the children of thy people, but thou shalt love thy neighbour as thyself: I am the LORD.
James identifies the Leviticus 19 neighbor-love statute as the 'royal law' — the supreme covenant ordinance against which partiality is measured. The statute established neighbor-love as the positive expression of the entire network of neighbor-directed covenant obligations. James's identification of it as royal establishes its constitutional supremacy: the Leviticus 19 love-ordinance functions as the covenant's constitutional king, the supreme standard that comprehends and evaluates all other covenant conduct.
James 2:10-11
For whosoever shall keep the whole law, and yet offend in one point, he is guilty of all. For he that said, Do not commit adultery, said also, Do not kill. Now if thou commit no adultery, yet if thou kill, thou art become a transgressor of the law.
Exodus 20:13-14
Thou shalt not kill. Thou shalt not commit adultery.
James cites the sixth and seventh commandments to illustrate the Decalogue's unity as a single legislative body. The same lawgiver who prohibited adultery also prohibited murder — the two commandments come from the same constitutional source, making violation of one a violation of the whole lawgiver's authority. James's argument establishes the Exodus 20 Decalogue's constitutional indivisibility: breaking one commandment is not a partial violation but a violation of the entire covenant constitution, because all commandments derive their authority from the same divine lawgiver.
James 2:21-23
Was not Abraham our father justified by works, when he had offered Isaac his son upon the altar? Seest thou how faith wrought with his works, and by works was faith made perfect? And the scripture was fulfilled which saith, Abraham believed God, and it was imputed unto him for righteousness:
Genesis 22:1-2
And it came to pass after these things, that God did tempt Abraham, and said unto him, Abraham: and he said, Behold, here I am. And he said, Take now thy son, thine only son Isaac, whom thou lovest, and get thee into the land of Moriah; and offer him there for a burnt offering
James invokes the Genesis 22 binding of Isaac as the supreme demonstration of faith-completing works. The offering of Isaac was the covenant act that fulfilled the Genesis 15:6 faith-imputation — 'the scripture was fulfilled' — because the binding of Isaac demonstrated in works the reality of the faith that had been counted as righteousness decades earlier. Genesis 22 is the constitutional proof that Abraham's faith was genuine: genuine faith produces the covenant obedience that the binding of Isaac represents.
Genesis 15:6
And he believed in the LORD; and he counted it to him for righteousness.
James quotes Genesis 15:6 as the scriptural baseline of Abraham's justification by faith, establishing that the faith Paul also cites was real — and then showing that this genuine faith produced the works of Genesis 22. James's use of Genesis 15:6 establishes continuity with Paul's argument: both appeal to the same Genesis 15 text, but James shows that the faith that was counted as righteousness was the kind of living faith that Genesis 22 demonstrates.