This is because the Qa'im Al-Mahdi will kill Iblis and every disbeliever until the religion is entirely one. So Allah named that day the Day of Nowruz.

And the Persians named it Nowruz, meaning the "New Day," derived from the Light (Al-Nur).

And the attire and the swings (Marajih) that are made in it are a similitude (Mathal) of the striving (Sa'y) of bodies towards one another when they came to have spirits. As for the water that is poured in it for purification, it is the counterpart (Nazir) of the rain that rained upon the Luminous Bodies.

And what is burned of the Samajat ¹ is a similitude of the fire that resulted from the disobedience of Iblis, his offspring, and his genus. And the Samajat are a similitude of the devils, the offspring of Iblis, may Allah curse him.

This is what I have attained regarding the knowledge of the Batin of Nowruz. And Allah knows best the Unseen, and above every possessor of knowledge is a Knower. And I have not been given of knowledge except a little of what Allah bestowed upon me, and I transmitted it from our Sheikhs, may Allah sanctify their spirits and elevate their persons. By Muhammad and his Family.