There can be no doubt that the works of the law were required for Israel to obey. If they disobeyed they would not receive the blessing or righteousness of God (Deut 6:24-25).
Further it can be understood that Jesus in his ministry to Israel taught obedience to the law (Matt 5:19).
“Think not that I am come to destroy the law, or the prophets: I am not come to destroy, but to fulfil.” – Mat 5:17
Even beyond the death and resurrection of their King, the twelve apostles were taught to continue in obedience to the covenants (James 2:24, 1 John 2:3). As far along as Acts 20, James is zealous of the law.
“Thou seest, brother, how many thousands of Jews there are which believe; and they are all zealous of the law:” – Acts 20:21
Yet, we know that works cannot save a man from sin (Rom 3:20).
The Mystery Truth
Before the dispensation of grace men would plead for God’s mercy and grace to forgive their sins (Psalm 51:11). God responded with appropriate forgiveness when asked with a contrite heart (Psalm 51:17). Yet, they did not understand how God could be just and the justifier.
It was not until the revealed mystery of Christ to Paul that all men could know how God could be just and the justifier (Rom 3:26, 4:5). Through the manifold wisdom of God, Paul explains what was kept secret since the beginning of the world: how God would impute free righteousness unto all men upon all who believed in the cross of Christ (2 Cor 5:21).
Paul makes it clear when he says:
“For by grace are ye saved through faith; and that not of yourselves: it is the gift of God: Not of works, lest any man should boast.” – Eph 2:8-9
All Saved by Grace
The mystery of Christ explains how all men at all times can only be saved by grace through faith, not of works. However, only in this dispensation grace stands unaccompanied by any required works. This is because of the substitutionary nature of Christ’s work applied to you.
Though Old Testament saints were never saved by their works, they had no knowledge of the mystery of Christ. They could not put their faith in something that was a secret. Their faith was in the testament. The testament required obedience to works.
The New Testament saints could also never be saved by their works; however, they too had no knowledge of the mystery and placed their faith in a better testament (Heb 7:22). The better testament required obedience to works to remain in the covenant (Heb 10:23-26).
Future Salvation Comes
Israel’s salvation is yet in the future as it is there that the testament will be fulfilled.
“And so all Israel shall be saved: as it is written, There shall come out of Sion the Deliverer, and shall turn away ungodliness from Jacob: For this is my covenant unto them, when I shall take away their sins.” – Rom 11:26-27
It was not until Peter heard Paul disputing in Jerusalem about his God given authority to teach the mystery dispensation of grace that he makes the comment:
“But we believe that through the grace of the Lord Jesus Christ we shall be saved, even as they.” – Acts 15:11
They have a covenant, we do not. They will be saved in the future even as we are presently, by grace, but not yet. Peter says to his remnant:
“Wherefore gird up the loins of your mind, be sober, and hope to the end for the grace that is to be brought unto you at the revelation of Jesus Christ;” – 1 Peter 1:13
Their time of perfection will come (James 1:4). You stand complete in Christ now (Col 2:10).