Yes, but it was always that way. Paul’s whole point in Romans is that Jews and Gentiles are saved the same way, and always were.
When were Gentiles included? Was it always or when the eligibility criteria was removed?
Jesus and the rich young man only talk about part of it, presumably because the young man already understood what every Jew understood: Israel was God’s people solely through God’s grace; they certainly didn’t merit being chosen from the nations. Having been chosen (justified would be Paul’s term) without merit, they were then responsible for keeping the commandments. For Jesus that’s the 10 commandments, but we see elsewhere that he had a unique take on those commandments that turned them more into a statement of the need to love God and neighbor than legal requirements.
They were chosen without merit and were to manifest the ability to survive even living selflessly, thus showing what God desired could be performed, thereby turning humanity to God, a fulfillment of the promise to Abraham. However, their cowardice led them to ask for a contract that protected their lives.
Jeremiah 7
22“For I did not speak to your fathers, or command them in the day that I brought them out of the land of Egypt, concerning burnt offerings and sacrifices. 23“But this is what I commanded them, saying, ‘Obey My voice, and I will be your God, and you will be My people; and you will walk in all the way which I command you, that it may be well with you.’
God did not want that contract, but gave it to them, since it served another purpose, it revealed sin. It showed what happened to defaulters, death, the body of the sacrifice was cut in half,and circumcision was the symbol of that penalty. This Covenant did not, could not, replace the original Covenant, the unconditional promise to Abraham that his descendants, identified by loyalty, would gather God's lost sheep. It was added on top of the original Covenant. Those who observed works of the law would be protected from wrath. Those who were loyal to God, feared Him and did what was right, they would become the means through which the world would be blessed.
Interestingly, Jesus told the rich young man to follow only those commands of loyalty to God, since death no longer was a penalty. He was going to end that contract, with the cross.
Paul tells us that this arrangement has now been expanded to include Gentiles. They are also justified by grace through faith, just as Israel was. And they are also expected to abide by the commandments — with Jesus’ understanding of them — and would be held accountable for doing so.
The difference is not that Gentiles were now included, since they always were, but without a Covenant. The difference is that Gentiles would now be allowed to manifest the Kingdom of God in a special Way, living selfless lives and not losing out, because the Finger of God sustained the believer, but also because the Sabbath Rest prefigured in Law was now a reality in Christ. He who was without sin had been made a sin offering, so that in Him, all believers, not just Jew, could become the righteousness of God, the fulfilment of His promise to Abraham that those in his Seed would become blessings to the world in the same way Christ was a blessing.
Of course Jesus adds a new element to the picture. We now have the new covenant, which writes the law into our hearts. But the fundamental scheme is the same: justified by grace and accountable for how we live in response.
The Old Covenant was written on a stone tablet, was a job description, circumcision of the male child, to reveal the penalty of sin, cutting in half, death, in return for escaping wrath, just like circumcision of Zephaniah's child, was compensated by turning away wrath from Moses. The New Covenant was written on the heart, requiring internalising the character of God, as befitting co-heirs with Christ, sons. The family member never works for a wage, but works to protect what already belongs to him, family.
