Isaiah 66:18

"And I, because of their actions and imaginations, am about to come and gather all nations and tongues, and they will come and see my glory"

because of their actions and imaginations
Proverbs 24:1-2 Do not envy wicked men, do not desire their company; for their hearts plot violence, and their lips talk about making trouble.
Isaiah 65:2 "All day long I have held out my hands to an obstinate people, who walk in ways not good, pursuing their own imaginations--"

am about to come and gather all nations
Isaiah 2:3 Many peoples will come and say, "Come, let us go up to the mountain of the LORD, to the house of the God of Jacob. He will teach us his ways, so that we may walk in his paths." The law will go out from Zion, the word of the LORD from Jerusalem.
Joel 3:2 I will gather all nations and bring them down to the Valley of Jehoshaphat. There I will enter into judgment against them concerning my inheritance, my people Israel, for they scattered my people among the nations and divided up my land.
Zephaniah 3:8 "Therefore wait for me," declares the LORD, "for the day I will stand up to testify. I have decided to assemble the nations, to gather the kingdoms and to pour out my wrath on them--all my fierce anger. The whole world will be consumed by the fire of my jealous anger."
Zechariah 12:3 On that day, when all the nations of the earth are gathered against her, I will make Jerusalem an immovable rock for all the nations. All who try to move it will injure themselves.
Zechariah 14:2 I will gather all the nations to Jerusalem to fight against it; the city will be captured, the houses ransacked, and the women raped. Half of the city will go into exile, but the rest of the people will not be taken from the city.

they will come and see my glory
Exodus 16:7 "... and in the morning you will see the glory of the LORD, because he has heard your grumbling against him. Who are we that you should grumble against us?"
Isaiah 35:2-4 ... it will burst into bloom; it will rejoice greatly and shout for joy. The glory of Lebanon will be given to it, the splendor of Carmel and Sharon; they will see the glory of the LORD, the splendor of our God. Strengthen the feeble hands, steady the knees that give way; say to those with fearful hearts, "Be strong, do not fear; your God will come, he will come with vengeance; with divine retribution he will come to save you."
Isaiah 40:5 "And the glory of the LORD will be revealed, and all mankind together will see it. For the mouth of the LORD has spoken it."
Isaiah 59:19 From the west, men will fear the name of the LORD, and from the rising of the sun, they will revere his glory. For he will come like a pent-up flood that the breath of the LORD drives along.

Scriptures taken from the Holy Bible, New International Version® NIV®, Copyright© 1973, 1978, 1984 by International Bible Society. Used by permission. All rights reserved worldwide.