Rom 11:25, Rom 15:9-11, Rev 15:4

In the Old Testament, God said that the Israelites would not honor God, but the Gentiles would fear God. (Mal 1:11-12)

Mal 1:11 For from the rising of the sun even unto the going down of the same my name shall be great among the Gentiles; and in every place incense shall be offered unto my name, and a pure offering: for my name shall be great among the heathen, saith the Lord of hosts. 12 But ye have profaned it, in that ye say, The table of the Lord is polluted; and the fruit thereof, even his meat, is contemptible.

God made the Gentiles glorify God by believing in Jesus as the Christ. (Romans 15:9-11, Revelation 15:4)

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.

Revelation 15:4 Who shall not fear thee, O Lord, and glorify thy name? for thou only art holy: for all nations shall come and worship before thee; for thy judgments are made manifest.

Until all the Gentiles who will be saved are saved, the people of Israel will become hardened and will not believe that Jesus is the Christ. (Rom 11:25)

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 of the Gentiles be come in.