The idea that strong nations would bow to the God of Israel would have sounded absurd to the listeners of Isiah. Israel was wedged between the Assyrian / Babylonian empire (one became the other) to the North and East, and Egypt to the South. The Western depredations from the Punic hegemony remained an issue. They were not that wealthy, and had not been since Solomon's death.
But strong nations, that built empires where the son did not set, did so for God and King: the God they worshipped was Christ. Isaiah foreshadowed that.
25 O Lord, You are my God;
I will exalt You, I will give thanks to Your name;
For You have worked wonders,
Plans formed long ago, with perfect faithfulness.
2 For You have made a city into a heap,
A fortified city into a ruin;
A palace of strangers is a city no more,
It will never be rebuilt.
3 Therefore a strong people will glorify You;
Cities of ruthless nations will revere You.
4 For You have been a defense for the helpless,
A defense for the needy in his distress,
A refuge from the storm, a shade from the heat;
For the breath of the ruthless
Is like a rain storm against a wall.
5 Like heat in drought, You subdue the uproar of aliens;
Like heat by the shadow of a cloud, the song of the ruthless is silenced.
1 Peter 1:8-12
8 and though you have not seen Him, you love Him, and though you do not see Him now, but believe in Him, you greatly rejoice with joy inexpressible and full of glory, 9 obtaining as the outcome of your faith the salvation of your souls.
10 As to this salvation, the prophets who prophesied of the grace that would come to you made careful searches and inquiries, 11 seeking to know what person or time the Spirit of Christ within them was indicating as He predicted the sufferings of Christ and the glories to follow. 12 It was revealed to them that they were not serving themselves, but you, in these things which now have been announced to you through those who preached the gospel to you by the Holy Spirit sent from heaven—things into which angels long to look.
Pete's note that the prophets talked about Christ for our benefit then leaves us with a consequence. For those to whom much is given, much is required. Peter reminds us of the greatness of the gifts we have.
So let us ignore those who would have us fear. God loves us more than we imagine. Let us seek him, and he will give us peace.