The inclusion of the Gentiles into the "people of God" at the end of time was not an afterthought or a response to Jewish particularism. Rather the ingathering of the nations had always been a common theme in the Hebrew prophetic understanding of God's future.
Even the election of Abraham (Genesis 12:2-3) included the Gentile nations. God promised
To bless Abraham.
To make him a great nation.
To make his name great.
To give him innumerable descendants (like the sands of the sea).
To bless those that blessed Abraham and to curse those that cursed him.
To bless all nations through Abraham and his offspring.
Abraham and, in turn, his descendants Israel were the elect of God, chosen to receive the oracles of God and then to become a priesthood to all nations. The one true God was not the God of Israel alone, but the God of all. Israel was selected for a specific purpose: to act as God's agent in the world, bringing his law and glory to all nations.
This was also the message of Jesus and Paul. They both looked for the impending restoration of Israel and the ingathering of the nations. It was not accidental that Jesus stated emphatically that the end could not come until the gospel had been proclaimed in all nations. It is not accidental that Jesus' final and great commission was to "make disciples" in all of the world. It is not accidental that Peter appealed to the Hebrew prophet Joel in his Pentecostal sermon to explain that the great endtime outpouring of the Spirit on all peoples had already begun.
The inclusion of the Gentiles in the "people of God" is a Bible-wide message. Neither Jesus nor Paul were innovators here. Rather they shared the confidence of the Hebrew prophets that God's "age to come" would include the Gentiles. With the Hebrew prophets, they looked for the near--perhaps even present--(1) unveiling of God's identity and glory to all peoples, (2) eschatological pilgrimage of the nations to the mountain of God, (3) great messianic feast of table fellowship, and (4) bearing of gifts to Zion by the endtime Gentile pilgrims.
Listen to the expectations of the Hebrew prophets and hear them echo in Jesus' preaching of the kingdom of God and Paul's mission to the Gentile nations.
Unveiling of God's Identity and Glory to All Peoples
Joel 2: 28-29
And it shall come to pass afterward that I will pour out My Spirit on all flesh; Your sons and your daughters shall prophesy, your old men shall dream dreams, your young men shall see visions. And also on My menservants and on My maidservants I will pour out My Spirit in those days.
Assemble yourselves and come; draw near together, you who have escaped from the nations. They have no knowledge, who carry the wood of their carved image, and pray to a god that cannot save. Tell and bring forth your case; Yes, let them take counsel together. Who has declared this from ancient time? Who has told it from that time? Have not I, the Lord? And there is no other God besides Me, a just God and a Savior; There is none besides Me. “Look to Me, and be saved, All you ends of the earth! For I am God, and there is no other. I have sworn by Myself; The word has gone out of My mouth in righteousness, and shall not return, that to Me every knee shall bow, every tongue shall take an oath.
Isaiah 49:3 and 6
‘You are My servant, O Israel, In whom I will be glorified.’ . . . It is too small a thing that You should be My Servant to raise up the tribes of Jacob, and to restore the preserved ones of Israel; I will also give You as a light to the Gentiles, that You should be My salvation to the ends of the earth.
Sing and rejoice, O daughter of Zion! For behold, I am coming and I will dwell in your midst,” says the Lord. “Many nations shall be joined to the Lord in that day, and they shall become My people. And I will dwell in your midst. Then you will know that the Lord of hosts has sent Me to you.
Eschatological Pilgrimage of the Nations to the Mountain of God
Isaiah 2:2-4 (Micah 4:1-3)
Now it shall come to pass in the latter days that the mountain of the Lord’s house shall be established on the top of the mountains, and shall be exalted above the hills; and all nations shall flow to it. Many people shall come and say, “Come, and let us go up to the mountain of the Lord, to the house of the God of Jacob; He will teach us His ways, and we shall walk in His paths.” For out of Zion shall go forth the law, and the word of the Lord from Jerusalem.He shall judge between the nations, and rebuke many people; they shall beat their swords into plowshares, and their spears into pruning hooks; nation shall not lift up sword against nation, neither shall they learn war anymore.
Surely you shall call a nation you do not know, and nations who do not know you shall run to you, because of the Lord your God, and the Holy One of Israel; for He has glorified you.
Also the sons of the foreigner who join themselves to the Lord, to serve Him, and to love the name of the Lord, to be His servants—everyone who keeps from defiling the Sabbath, and holds fast My covenant—even them I will bring to My holy mountain, And make them joyful in My house of prayer. Their burnt offerings and their sacrifices will be accepted on My altar; for My house shall be called a house of prayer for all nations.
At that time Jerusalem shall be called The Throne of the Lord, and all the nations shall be gathered to it, to the name of the Lord, to Jerusalem. No more shall they follow the dictates of their evil hearts.
Thus says the Lord of hosts: ‘Peoples shall yet come, inhabitants of many cities; The inhabitants of one city shall go to another, saying, “Let us continue to go and pray before the Lord, and seek the Lord of hosts. I myself will go also.” Yes, many peoples and strong nations shall come to seek the Lord of hosts in Jerusalem, and to pray before the Lord.’ “Thus says the Lord of hosts: ‘In those days ten men from every language of the nations shall grasp the sleeve of a Jewish man, saying, “Let us go with you, for we have heard that God is with you.
Great Messianic Feast of Table Fellowship
And in this mountain the Lord of hosts will make for all people a feast of choice pieces, a feast of wines on the lees, of fat things full of marrow, of well-refined wines on the lees. And He will destroy on this mountain the surface of the covering cast over all people, and the veil that is spread over all nations. He will swallow up death forever, and the Lord God will wipe away tears from all faces; the rebuke of His people. He will take away from all the earth; for the Lord has spoken.
And it shall come to pass that everyone who is left of all the nations which came against Jerusalem shall go up from year to year to worship the King, the Lord of hosts, and to keep the Feast of Tabernacles.
And I say to you that many will come from east and west, and sit down with Abraham, Isaac, and Jacob in the kingdom of heaven. But the sons of the kingdom will be cast out into outer darkness. There will be weeping and gnashing of teeth.
Let us be glad and rejoice and give Him glory, for the marriage of the Lamb has come, and His wife has made herself ready. And to her it was granted to be arrayed in fine linen, clean and bright, for the fine linen is the righteous acts of the saints. Then he said to me, “Write: ‘Blessed are those who are called to the marriage supper of the Lamb!’” And he said to me, “These are the true sayings of God.”
Bearing of Gifts by Gentile Pilgrims to Zion
Isaiah 60:11 (See entire chapter about gifts from Gentiles)
Therefore your gates [Jerusalem] shall be open continually; they shall not be shut day or night, that men may bring to you the wealth of the Gentiles, and their kings in procession.
For I know their works and their thoughts. It shall be that I will gather all nations and tongues; and they shall come and see My glory. . . And they shall declare My glory among the Gentiles. Then they shall bring all your brethren for an offering to the Lord out of all nations, on horses and in chariots and in litters, on mules and on camels, to My holy mountain Jerusalem,” says the Lord, “as the children of Israel bring an offering in a clean vessel into the house of the Lord. And I will also take some of them for priests and Levites,” says the Lord.
Matthew 2:1-2, 9-11
Now after Jesus was born in Bethlehem of Judea in the days of Herod the king, behold, wise men from the East came to Jerusalem, saying, “Where is He who has been born King of the Jews? For we have seen His star in the East and have come to worship Him.” . . . And when they had come into the house, they saw the young Child with Mary His mother, and fell down and worshiped Him. And when they had opened their treasures, they presented gifts to Him: gold, frankincense, and myrrh.
But now I am going to Jerusalem to minister to the saints. For it pleased those from Macedonia and Achaia to make a certain contribution for the poor among the saints who are in Jerusalem. It pleased them indeed, and they are their debtors. For if the Gentiles have been partakers of their spiritual things, their duty is also to minister to them in material things.
I Corinthians 16:1-4
Now concerning the collection for the saints, as I have given orders to the churches of Galatia, so you must do also: On the first day of the week let each one of you lay something aside, storing up as he may prosper, that there be no collections when I come. And when I come, whomever you approve by your letters I will send to bear your gift to Jerusalem. But if it is fitting that I go also, they will go with me.