Rom 15:9-12, Rom 16:26, Mt 28:18-20, Mk 16:15, Acts 1:8

In the Old Testament, God said that He would spread His glory to the nations. (Isa 66:18-19)

Isa 66:18 For I know their works and their thoughts: it shall come, that I will gather all nations and tongues; and they shall come, and see my glory. 19 And I will set a sign among them, and I will send those that escape of them unto the nations, to Tarshish, Pul, and Lud, that draw the bow, to Tubal, and Javan, to the isles afar off, that have not heard my fame, neither have seen my glory; and they shall declare my glory among the Gentiles.

The nations have hope in Christ who will save them and bring glory to God. (Romans 15:9-12)

Romans 15:9 And that the Gentiles might glorify God for his mercy; as it is written, For this cause I will confess to thee among the Gentiles, and sing unto thy name. 10 And again he saith, Rejoice, ye Gentiles, with his people. 11 And again, Praise the Lord, all ye Gentiles; and laud him, all ye people. 12 And again, Esaias saith, There shall be a root of Jesse, and he that shall rise to reign over the Gentiles; in him shall the Gentiles trust.

As prophesied in the Old Testament, all nations will believe in Christ and obey God. (Romans 16:26)

Romans 16:26 But now is made manifest, and by the scriptures of the prophets, according to the commandment of the everlasting God, made known to all nations for the obedience of faith:

We must tell all nations that Jesus is the Christ. (Mt 28:18-20, Mark 16:15, Acts 1:8)

Mt 28:18 And Jesus came and spake unto them, saying, All power is given unto me in heaven and in earth. 19 Go ye therefore, and teach all nations, baptizing them in the name of the Father, and of the Son, and of the Holy Ghost: 20 Teaching them to observe all things whatsoever I have commanded you: and, lo, I am with you always, even unto the end of the world. Amen.

Mark 16:15 And he said unto them, Go ye into all the world, and preach the gospel to every creature.

Acts 1:8 But ye shall receive power, after that the Holy Ghost is come upon you: and ye shall be witnesses unto me both in Jerusalem, and in all Judaea, and in Samaria, and unto the uttermost part of the earth.