And I will select some of them also to be priests and Levites

Isaiah 66:15-24

For with fire and with his sword the Lord will execute judgment on all people, and many will be those slain by the Lord.

“Those who consecrate and purify themselves to go into the gardens, following one who is among those who eat the flesh of pigs, rats and other unclean things—they will meet their end together with the one they follow,” declares the Lord.

I will set a sign among them, and I will send some of those who survive to the nations—to Tarshish, to the Libyans[b] and Lydians (famous as archers), to Tubal and Greece, and to the distant islands that have not heard of my fame or seen my glory. They will proclaim my glory among the nations.

And I will select some of them also to be priests and Levites,” says the Lord.

As the new heavens and the new earth that I make will endure before me,” declares the Lord, “so will your name and descendants endure. From one New Moon to another and from one Sabbath to another, all mankind will come and bow down before me,” says the Lord.  “And they will go out and look on the dead bodies of those who rebelled against me; the worms that eat them will not die, the fire that burns them will not be quenched, and they will be loathsome to all mankind.”

Why?

Christians of can not keep the Holy life will be discarded by the Lord, suffer the fire, and fir punished.