Faith is explicitly stated to be "by grace" and thus not a work and Paul repeatedly states Abraham was justified by faith and not by works:
Rom. 4:3 For what saith the scripture? Abraham believed God, and it was counted unto him for righteousness.
4 Now to him that worketh is the reward not reckoned of grace, but of debt.
5 But to him that worketh not, but believeth on him that justifieth the ungodly, his faith is counted for righteousness.
6 Even as David also describeth the blessedness of the man, unto whom God imputeth righteousness without works,
It does not take a lot of reading skill to see that Paul plainly and repeatedly contrasts works with faith in the above text. Do you need to go back to elementary school and learn to read all over again????? That must be the case if you insist faith/beleiving is works:
"BUT TO HIM THAT WORKETH NOT BUT BELEIVETH....HIS FAITH IS COUNTED FOR RIGHTEOUSNESS."
What event in history took place that removed the elect of God from being under the law, (a schoolmaster)?
Rom. 3:21 YLT
And now apart from law (from being under the law) hath the righteousness of God
been manifested, (How? By the death of the Christ) testified to by the law and the prophets, (God will provide himself a lamb. The passover sacrificed for us, justifies.)
What does Paul call that moment in history that manifested being removed from being under the law.
Rom. 3:22 YLT and the righteousness of God
through the faith of Jesus Christ to all, and upon all those believing, -- for there is no difference,
It was through the faith of Christ (Jesus dying on the cross) the Holy Spirit was given. That is where and how the Holy Spirit came to be shed on the elect, the firstfruits of the Spirit. God the Father Gal. 1:1 by the renewing of the Holy Spirit Titus 3:5 and Romans 8:11 raised Jesus from the dead, Gal.1:1. We then by the shed blood of Jesus, his death, his faith were justified (imputed with the righteousness of God) and we shall be (by resurrection/instant change) saved by his (resurrected) life.
John 16:7 Nevertheless I tell you the truth; It is expedient for you that I go away:
for if I go not away, the Comforter will not come unto you; but if I depart, I will send him unto you.
He went away, died, obedience of faith, therefore the Father by grace through the faith of Jesus raised him from the dead, the gift of God exalted Jesus on high and sent the Holy Spirit through Jesus his Son.
Why did Paul believe this? Because Jesus the Son of God himself called him?
Why did Abraham believe? Because God called him and through the faith to come, the Lamb slain from the foundation of the world, God imputed the righteousness of God to Abraham.
The sheep of God.
Acts 26:18 To open their eyes, to turn from darkness to light, and the power of Satan unto God, that they may receive forgiveness of sins, and inheritance among them which are sanctified by faith that is in me.
That is why Paul says, Christ in you, the hope of glory.
Jesus is out faith. He is the substance of things hoped for the evidence of things not seen.