How does envy affect a person, causing illness, death, or poverty? What is the nature of this material effect? Does this contradict the written divine decree and destiny (Qadaa and Qadar)? And does Surah Al-Falaq protect from the envier?

The impact of envy (hasad) and the evil eye (ayn) is established in the Qur'an and Sunnah. Allah Almighty says: "And indeed, those who disbelieved would almost make you slip with their eyes" (Qur'an 68:51). In the Prophet's Sunnah, the Prophet, peace and blessings be upon him, said: "The evil eye is real, and if anything were to precede divine decree, the evil eye would precede it." Ibn Al-Qayyim clarified that the evil eye is an arrow that emanates from the soul of the envious person or the one casting the eye, striking the envied person. If it finds them exposed, it affects them; but if it finds them fortified, it does not affect them. The origin of its effect lies in the admiration of the one casting the eye for something, which is then followed by the workings of their malicious soul.