James says that Abraham showed his righteouness by his offereing of Isaac,
How was it shown?18 And in thy seed shall all the nations of the earth be blessed; because thou hast obeyed my voice.Obedience.
Except that the issue is not how Abraham showed his righteousness," but rather, ...
... how Abraham acquired his righteousness".Genesis 15:2 And Abram said, Lord GOD, what wilt thou give me, seeing I go childless, and the steward of my house is this Eliezer of Damascus?
3 And Abram said, Behold, to me thou hast given no seed: and, lo, one born in my house is mine heir.
4 And, behold, the word of the LORD came unto him, saying, This shall not be thine heir; but he that shall come forth out of thine own bowels shall be thine heir.
5 And he brought him forth abroad, and said, Look now toward heaven, and tell the stars, if thou be able to number them: and he said unto him, So shall thy seed be.
6 And he believed in the LORD; and he counted it to him for righteousness.
Lexicon Greek 1343 [ from the root of 1342]
dikaiosune {dik-ah-yos-oo'-nay}
1) in a broad sense: state of him who is as he ought to be, righteousness, the condition acceptable to God
a) the doctrine concerning the way in which man may attain a state approved of God
b) integrity, virtue, purity of life, rightness, correctness of thinking feeling, and acting
2) in a narrower sense, justice or the virtue which gives each his due
Lexicon Greek 1342 dikaios {dik'-ah-yos}
1) righteous, observing divine laws
a) in a wide sense, upright, righteous, virtuous, keeping the commands of God
1) of those who seem to themselves to be righteous, who pride themselves to be righteous, who pride themselves in their virtues, whether real or imagined
2) innocent, faultless, guiltless
3) used of him whose way of thinking, feeling, and acting is wholly conformed to the will of God, and who therefore needs no rectification in the heart or life
a) only Christ truly
4) approved of or acceptable of God
b) in a narrower sense, rendering to each his due and that in a judicial sense, passing just judgment on others, whether expressed in words or shown by the manner of dealing with them
Genesis 26
4 And I will make thy seed to multiply as the stars of heaven, and will give unto thy seed all these countries; and in thy seed shall all the nations of the earth be blessed;
5 Because that Abraham obeyed my voice, and kept my charge, my commandments, my statutes, and my laws.
righteous from the Hebrew
6662 tsaddiyq tsad-deek' from 6663; just:--just, lawful, righteous (man).
1) just, lawful, righteous
a) just, righteous (in government)
b) just, right (in one's cause)
c) just, righteous (in conduct and character)
d) righteous (as justified and vindicated by God)
e) right, correct, lawful