The “Romans” of Paul’s Epistles were Israelites of both Zarah-Judah and Pharez-Judah, who living in the city of Rome.

https://www.youtube.com/watch?v=UZB4iCEDZuY&feature=youtu.be

Rom 11:25  For I would not, brethren, that ye should be ignorant of this mystery, lest ye should be wise in your own conceits; that blindness in part is happened to Israel, until the fulness (completion, copiousness) of the nations be come in.
Rom 11:26  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:
Rom 11:27  For this is my covenant unto them, when I shall take away their sins.
Rom 11:28  As concerning the gospel, they are enemies for your sakes: but as touching the election, they are beloved for the fathers’ sakes.
Rom 11:29  For the gifts and calling of God are without repentance.

Paul is not making a prediction here of future sins being forgiven.  He is quoting Old Testaments prophecy concerning Calvary.

Isaiah 59:20-21:

Isa 59:20  And the Redeemer shall come to Zion, and unto them that turn from transgression in Jacob, saith the LORD.
Isa 59:21  As for me, this is my covenant with them, saith the LORD; My spirit that is upon thee, and my words which I have put in thy mouth, shall not depart out of thy mouth, nor out of the mouth of thy seed, nor out of the mouth of thy seed’s seed, saith the LORD, from henceforth and for ever.

ONLY OUR PAST SINS WERE FORGIVEN AT CALVARY:

Romans 3:25.  Whom God hath set forth to be a propitiation through faith in His blood, to declare His righteousness for the remission of SINS THAT ARE PAST, through the forbearance of God.

            Hebrews 9:15.  And for this cause He is the Mediator of the New Testament, that by means of death, for the REDEMPTION OF THE TRANSGRESSIONS THAT WERE UNDER THE FIRST TESTAMENT, they which are called MIGHT receive the promise of eternal inheritance.

            II Peter 1:9.  But he that lacketh these things is blind, and cannot see afar off, and hath forgotten that HE WAS PURGED FROM HIS OLD SINS.

            These three verses prove the fallaciousness of the dispensationalist claim that all sins, even those committed after the Cross, have been forgiven or will be forgiven without any fear of punishment.   In the above verses, Paul and Peter are very clear in stating that only those old sins committed under the Old Covenant were forgiven at the cross.  There is no blanket forgiveness of future sins, even for Israel.  That concept is pure invention by the Scofield crowd.

            Paul directly contradicts this notion at Hebrews 10:26-27: 

            “For if we sin willfully after we have received the knowledge of the truth, there remains no sacrifice for sins, but a certain fearful looking for of judgment and fiery indignation, which shall devour the adversaries.”