Not sure I totally agree.
***Romans 4 spells out OT faith
What then shall we say that Abraham, our forefather, discovered in this matter? 2 If, in fact, Abraham was justified by works, he had something to boast about--but not before God. 3 What does the Scripture say? "Abraham believed God, and it was credited to him as righteousness." 4 Now when a man works, his wages are not credited to him as a gift, but as an obligation. 5 However, to the man who does not work but trusts God who justifies the wicked, his faith is credited as righteousness. 6 David says the same thing when he speaks of the blessedness of the man to whom God credits righteousness apart from works: 7 "Blessed are they whose transgressions are forgiven, whose sins are covered. 8 Blessed is the man whose sin the Lord will never count against him." 9 Is this blessedness only for the circumcised, or also for the uncircumcised? We have been saying that Abraham's faith was credited to him as righteousness. 10 Under what circumstances was it credited? Was it after he was circumcised, or before? It was not after, but before! 11 And he received the sign of circumcision, a seal of the righteousness that he had by faith while he was still uncircumcised. So then, he is the father of all who believe but have not been circumcised, in order that righteousness might be credited to them. 12 And he is also the father of the circumcised who not only are circumcised but who also walk in the footsteps of the faith that our father Abraham had before he was circumcised.
***So salvation for the Jews was in faith looking forward to the coming of the Lord. And faith now is receiving the gift.
***Note.. Romans is expanding on an OT vs from Gen 15 1-6
After these things the word of the Lord came to Abram in a vision: cFear not, Abram, I am dyour shield; your reward shall be very great. 2 But Abram said, O Lord God, what will you give me, for I continue1 childless, and the heir of my house is Eliezer of Damascus? 3 And Abram said, Behold, you have given me no offspring, and ea member of my household will be my heir. 4 And behold, the word of the Lord came to him: This man shall not be your heir; fyour very own son2 shall be your heir. 5 And he brought him outside and said, Look toward heaven, and gnumber the stars, if you are able to number them. Then he said to him, hSo shall your offspring be. 6 And ihe believed the Lord, and He counted it to him as righteousness.