einstein quote about world war 3 - ReYep
It is Einstein's answer to the question of which new weapons will be used in the 3rd World War, at the dinner he attended with a group of friends in March 1947.

He said approximately: “I don't know what weapons could be used in World War 3. However. There is no doubt about what weapons will be used in World War 4.

To this answer, one of those present asked, "So what are they?" , and he finally answered "stone spears".
Einstein might not have actually said this, but other things that he said show that he believed the weapons used in World War III might be so devastating that they would end civilization as we know it
there is some debate about whether he actually said or wrote this exact phrase. The sentiment expressed in the quote is consistent with Einstein's concerns about the destructive potential of nuclear weapons, and he did make statements and write articles warning about the dangers of nuclear war and the need for peace.

Regardless of the exact wording, the quote is commonly associated with Einstein as a reflection of his views on the devastating consequences of global conflict and the importance of preventing future wars, especially those involving nuclear weapons.