Isaiah 51:
1 Listen to Me, you who follow after righteousness,
You who seek the Lord:
Look to the rock from which you were hewn,
And to the hole of the pit from which you were dug.
2 Look to Abraham your father,
And to Sarah who bore you;
For I called him alone,
And blessed him and increased him.
7 Listen to Me, you who know righteousness,
You people in whose heart is My law....
9 Awake, awake, put on strength,
O arm of the Lord!
Awake as in the ancient days,
In the generations of old....
Did Abraham keep the Torah?
Yes, without having a codified law from the hand of Moses.
We also see Isaac and Jacob hearing from the Lord, and obeying His Voice.
Genesis 26:
1 There was a famine in the land, besides the first famine that was in the days of Abraham.
And Isaac went to Abimelech king of the Philistines, in Gerar.
2 Then the Lord appeared to him and said: Do not go down to Egypt; live in the land
of which I shall tell you.
3 Dwell in this land, and I will be with you and bless you; for to you and your descendants
I give all these lands, and I will perform the oath which I swore to Abraham your father.
4 And I will make your descendants multiply as the stars of heaven; I will give to your
descendants all these lands; and in your seed all the nations of the earth shall be blessed;
5 because Abraham obeyed My voice and kept My charge, My commandments,
My statutes, and My laws.
Did Isaac, like Abraham, obey the voice of the Lord and receive the blessing?
Yes he did!
12 Then Isaac sowed in that land, and reaped in the same year a hundredfold;
and the Lord blessed him.
13 The man began to prosper, and continued prospering until he became very prosperous;
14 for he had possessions of flocks and possessions of herds and a great number of servants.
So the Philistines envied him.
This is precisely what Paul is teaching in Romans 3 and 4.
This is to walk by faith, like Abraham.
Romans 3:
21 But now the righteousness of God apart from the law is revealed, being witnessed
by the Law and the Prophets,
22 even the righteousness of God, through faith in Jesus Christ, to all and on all who believe.
Romans 4:
13 For the promise that he would be the heir of the world was not to Abraham or to his seed
through the law, but through the righteousness of faith.
14 For if those who are of the law are heirs, faith is made void and the promise made of no effect...
We learn from the law and the prophets, to rightly comprehend Paul's teaching.
Isaiah 8:20 To the law and to the testimony! If they do not speak according to this word,
it is because there is no light in them.
Paul's teaching does not contradict either, but requires a sound comprehension of
"the promise and the oath", and the walk of faith by hearing and heeding the voice
of the Lord, like Abraham, Isaac, and Jacob.
Galatians 3:
7 Therefore know that only those who are of faith are sons of Abraham.
8 And the Scripture, foreseeing that God would justify the Gentiles by faith,
preached the gospel to Abraham beforehand, saying,
In you all the nations shall be blessed.
9 So then those who are of faith are blessed with believing Abraham.
Do you feel the need to be under a schoolmaster to walk in righteousness?
By all means do so, until you are able to discern His voice and walk by faith.
Galatians 3:
23 But before faith came, we were kept under guard by the law,
kept for the faith which would afterward be revealed.
24 Therefore the law was our tutor to bring us to Christ,
that we might be justified by faith.
25 But after faith has come, we are no longer under a tutor.
Galatians 5:
16 I say then: Walk in the Spirit, and you shall not fulfill the lust of the flesh.
17 For the flesh lusts against the Spirit, and the Spirit against the flesh; and
these are contrary to one another, so that you do not do the things that you wish.
18 But if you are led by the Spirit, you are not under the law.
You can keep the law, but you cannot be justified in doing so.
You must hear His voice and obey. This is to walk by faith.
This is to walk in the perfect law of liberty, while also
fulfilling the "righteous requirements of the law".
Romans 8:
3 For what the law could not do in that it was weak through the flesh,
God did by sending His own Son in the likeness of sinful flesh,
on account of sin: He condemned sin in the flesh,
4 that the righteous requirement of the law might be fulfilled in us
who do not walk according to the flesh but according to the Spirit.
Acts 13:
38 Therefore let it be known to you, brethren, that through this Man is preached
to you the forgiveness of sins;
39 and by Him everyone who believes is justified from all things from which
you could not be justified by the law of Moses.
40 Beware therefore, lest what has been spoken in the prophets come upon you:
41 Behold, you despisers, Marvel and perish!
For I work a work in your days,
A work which you will by no means believe,
Though one were to declare it to you.