كتاب العين
50  
The Evil Eye

Yahya related to me from Malik that he had heard from Bukayr ibn Abdullah ibn al-Ashajj from Ibn Atiya that the Messenger of Allah, may Allah bless him and grant him peace, said:

"There is no contagion, no hama and no serpent in a hungry belly. However, the possessor of sick livestock must not stop at the same place as the possessor of healthy livestock, but the possessor of healthy livestock may stop wherever he wishes."

They said, "Messenger of Allah, Why is that?" The Messenger of Allah, may Allah bless him and grant him peace, said, "It is harmful."



Note: The majority of scholars interpret this to mean that these things in and of themselves do not transmit or cause harm through supernatural or hidden means but that Allah is ultimately in control and any fearful superstition around these is false.
وَحَدَّثَنِي عَنْ مَالِكٍ، أَنَّهُ بَلَغَهُ عَنْ بُكَيْرِ بْنِ عَبْدِ اللَّهِ بْنِ الأَشَجِّ، عَنِ ابْنِ عَطِيَّةَ، أَنَّ رَسُولَ اللَّهِ صلى الله عليه وسلم قَالَ ‏"‏ لاَ عَدْوَى وَلاَ هَامَ وَلاَ صَفَرَ وَلاَ يَحُلَّ الْمُمْرِضُ عَلَى الْمُصِحِّ وَلْيَحْلُلِ الْمُصِحُّ حَيْثُ شَاءَ ‏"‏ ‏.‏ فَقَالُوا يَا رَسُولَ اللَّهِ وَمَا ذَاكَ فَقَالَ رَسُولُ اللَّهِ صلى الله عليه وسلم ‏"‏ إِنَّهُ أَذًى ‏"‏ ‏.‏
USC-MSA web (English) reference : Book 50, Hadith 18
Arabic reference : Book 50, Hadith 1732