When the Bible speaks of "the nations" its simply speaking of all people, except the Nation Israel. All other people are of "the nations," which we and the Bible itself refers to as "the Gentiles."

Not Matthew, Mark, or Luke; nor Peter, James, or John, but Paul alone wrote this and made this claim in Romans 11:13 by divine inspiration:

"For I (Paul) Speak To You Gentiles [Greek Ethnos, The Nations] Inasmuch As I Am THE Apostle Of The Gentiles [Nations]: I Magnify Mine Office" (Rom.11:13).

Note well that Paul did not magnify himself, but his office, to which he had been appointed by the glorified Lord Himself from heaven. In defending his apostleship before the Galatians he wrote:

"But I certify you, brethren, THAT THE GOSPEL WHICH WAS PREACHED OF ME is not after man. For I neither received it of man, neither was I taught it, BUT BY THE REVELATION OF JESUS CHRIST" (Gal. 1:11-12).

In many other passages the apostle claims to speak as a direct representative of Christ.

"For I (Paul) have received of the Lord that which also I delivered unto you, That the Lord Jesus the same night in which he was betrayed took bread:" (1 Corinthians 11:23)

"For I (Paul) delivered unto you first of all that which I also received, how that Christ died for our sins according to the scriptures;" (1 Corinthians 15:3)

"If ye have heard of the dispensation of the grace of God which is given me (Paul) to you-ward: 3 How that by revelation he (directly) made known unto me the mystery; (as I wrote afore in few words," (Ephesians 3:2-3)

"For this we say unto you by the word of the Lord, that we which are alive and remain unto the coming of the Lord shall not prevent them which are asleep." (1 Thessalonians 4:15)

This could not indicate more emphatically Paul's claim that his words were "the words of the Lord Jesus Christ," receiving them from the ascended Lord by direct revelation. Concerning Paul's "gospel of the grace of God," he wrote; "For I neither received it of man, neither was I taught it, but by the revelation of Jesus Christ." (Galatians 1:12)

To the Corinthians, who questioned this, the Apostle wrote: "…If I (Paul) come again I will not spare, since Ye Seek A Proof Of Christ Speaking In Me" (2cor.13:2-3).

Consider also;

"If any man think himself to be a prophet, or spiritual, let him acknowledge that the things that I (Paul) write unto you are the commandments of the Lord. (1 Corinthians 14:37)

"In the day when God shall judge the secrets of men by Jesus Christ according to my (Paul's) gospel. (Romans 2:16)

The proof of this claim?

To the believers at Corinth he wrote what he could have written to many thousands of others: "The seal of mine apostleship are ye in the Lord" (ICor.9:2). This verse is more easily seen here in the Amplified Bible. "Even if I am not considered an apostle (a special messenger) by others, at least I am one to you; for you are the seal (the certificate, the living evidence) of my apostleship in the Lord [confirming and authenticating it]." (1 Corinthians 9:2 (AMP)

This was overwhelming indeed, for Paul was used more than any other apostle to found churches and lead men into the knowledge and joy of salvation by the offering Of Jesus as Savior. Paul then reveals the "the mystery, which is CHRIST IN YOU the hope of glory" (Col 1:25-27, cf. Rom 16:25).