The English translation says forever. The Greek text does not.
Matthew 13:49So shall it be at the
end of the world: the angels shall come forth, and sever the wicked from among the just,
The word translated "world" is the same word they translated forever. It's aion. Now, why do you suppose they changed it from forever to world? It's because they're definition doesn't work. Jesus said, "so shall it be at the end of the aion:"
That begs the question if aion means forever or eternity, why is Jesus speaking of it ending? By definition forever or eternity don't end. Yet, right here in this passage Jesus says it does end. That leaves us with a decision to make. Who is correct, the theologians or Jesus? That's an easy choice for me.