Well lets go back and first take the verse and then the context.
1. The verse.
New International Version
Abram believed the LORD, and he credited it to him as righteousness.
New Living Translation
And Abram believed the LORD, and the LORD counted him as righteous because of his faith.
English Standard Version
And he believed the LORD, and he counted it to him as righteousness.
New American Standard Bible
Then he believed in the LORD; and He reckoned it to him as righteousness.
King James Bible
And he believed in the LORD; and he counted it to him for righteousness.
Holman Christian Standard Bible
Abram believed the LORD, and He credited it to him as righteousness.
International Standard Version
Abram believed the LORD, and it was credited to him as righteousness.
NET Bible
Abram believed the LORD, and the LORD considered his response of faith as proof of genuine loyalty.
GOD'S WORD® Translation
Then Abram believed the LORD, and the LORD regarded that faith to be his approval of Abram.
Jubilee Bible 2000
And he believed the LORD, and he counted it to him for righteousness.
King James 2000 Bible
And he believed in the LORD; and he counted it to him for righteousness.
American King James Version
And he believed in the LORD; and he counted it to him for righteousness.
American Standard Version
And he believed in Jehovah; and he reckoned it to him for righteousness.
Douay-Rheims Bible
Abram believed God, and it was reputed to him unto justice.
Darby Bible Translation
And he believed Jehovah; and he reckoned it to him [as] righteousness.
English Revised Version
And he believed in the LORD; and he counted it to him for righteousness.
Webster's Bible Translation
And he believed in the LORD; and he counted it to him for righteousness.
World English Bible
He believed in Yahweh; and he reckoned it to him for righteousness.
Young's Literal Translation
And he hath believed in Jehovah, and He reckoneth it to him -- righteousness.
Genesis 15:6 Abram believed the LORD, and he credited it to him as righteousness.
By the way you can check every major commentary on that verse at that link and you will find every one of them interpret it as faith = righteousness.
Looks like we have 18 versions that span maybe one thousand years of biblical translation and not a single includes the words works, obedience, or merit. However lets go way back and see what the original language said.
Here is the original; 15:6 καὶ ἐπίστευσεν Αβραμ τῷ θεῷ καὶ ἐλογίσθη αὐτῷ εἰς δικαιοσύνην
The word: 'aman is the word translated to believe. It is translated as "to believe" 44 times in the bible. It is never translated as obey, work, or merit a single time in the bible.
The word:
tsĕdaqah is the word translated as "righteousness". It is translated as righteousness 128 times in the bible and never translated as reward or anything similar.
So without a single doubt the verse it's self says faith = righteousness. The rules of exegesis is that a verse says what it appears to say unless proven otherwise. Only then is a subsurface meaning examined. So you must prove that that verse does not mean what it says so the context is the issue at this point.
The context is that Abraham at this point had done no work for God beyond believing him what so ever. This was at the commission of Abraham's role as patriarch. He had yet to even set out in order to accomplish what God commanded. There were no works (or virtually none) which he had yet done to even mention. This verse takes place during the initial events where God is laying out what he wants and what he will do. Even Abraham's faith in this verse is not about a thing he will do but about a thing God will do. His faith is in God's ability to grant him sons even though he is so old and it has nothing to do with any work of Abraham even in anticipation.
So instead of the context supplying any justification for claiming faith actually means works it in fact proves beyond doubt that faith meant faith.
Just as an illustration of how complex the Hermeneutics can get and how exact an interpretation can be I provide the following.
Pulpit CommentaryVerse 6. - And he believed in the Lord. The hiphil of the verb aman, to prop or stay, signifies to build upon, hence to rest one's faith upon; and this describes exactly the mental act of the patriarch, who reposed his confidence in the Divine character, and based his hope of a future seed on the Divine word. And he counted it to him. Ἐλογίσθη αὐτῷ (LXX.), which is followed by nearly all the ancient versions, and by Paul in
Romans 4:3; but the suffix ך (a feminine for a neuter, as in
Job 5:9;
Psalm 12:4;
Psalm 27:4; vide Glass, ' Phil,' lib. 3. cp. 1:19), clearly indicates the object of the action expressed by the verb הָשַׁב, to think, to meditate, and then to impute (λογίζομαι), followed by לְ of pers. and acc. of the thing (cf.
2 Samuel 19:20;
Psalm 32:2). The thing in this case was his faith in the Divine promise. For righteousness. צְדְקְהְ - εἰς δίκαιοσύνην (LXX.); neither for merit and justice (Rabbi Solomon, Jarchi, Ealiseh), nor as a proof of his probity (Gesenius, Rosenmüller); but unto and with a view to justification (
Romans 4:3), so that God treated him as a righteous person (A Lapide), not, however, in the sense that he was now "correspondent to the will of God both in character and conduct" (Keil), but in the sense that he was now before God accepted and forgiven' (Luther, Calvin, Murphy, Candlish), which "passive righteousness, however, ultimately wrought in him an "active righteousness of complete conformity to the Divine will" ('Speaker's Commentary').
Genesis 15:6 Abram believed the LORD, and he credited it to him as righteousness.
Sorry but I just do not see even the possibility of any argument against that verse meaning what it says.
I routinely grant a thing is arguable if it is even a little bit true but this seems so utterly cut and dried as to be absolute. Can you tell me which post it is you feel you did prove otherwise? I am in a hurry and might have missed it.