حَدَّثَنِي عَنْ مَالِكٍ، عَنْ حُمَيْدِ بْنِ قَيْسٍ الْمَكِّيِّ، أَنَّهُ قَالَ دُخِلَ عَلَى رَسُولِ اللَّهِ صلى الله عليه وسلم بِابْنَىْ جَعْفَرِ بْنِ أَبِي طَالِبٍ فَقَالَ لِحَاضِنَتِهِمَا ‏"‏ مَا لِي أَرَاهُمَا ضَارِعَيْنِ ‏"‏ ‏.‏ فَقَالَتْ حَاضِنَتُهُمَا يَا رَسُولَ اللَّهِ إِنَّهُ تَسْرَعُ إِلَيْهِمَا الْعَيْنُ وَلَمْ يَمْنَعْنَا أَنْ نَسْتَرْقِيَ لَهُمَا إِلاَّ أَنَّا لاَ نَدْرِي مَا يُوَافِقُكَ مِنْ ذَلِكَ ‏.‏ فَقَالَ رَسُولُ اللَّهِ صلى الله عليه وسلم ‏"‏ اسْتَرْقُوا لَهُمَا فَإِنَّهُ لَوْ سَبَقَ شَىْءٌ الْقَدَرَ لَسَبَقَتْهُ الْعَيْنُ ‏"‏ ‏.‏

Yahya related to me from Malik that Humayd ibn Qays al-Makkisaid, "A man came to the Messenger of Allah, may Allah bless him andgrant him peace, with the two sons of Jafar ibn Abi Talib. He said totheir nursemaid, 'Why do I see them so thin?' Their nursemaid said,'Messenger of Allah, the evil eye goes quickly to them. Nothing stopsus from asking someone to make incantations (using ayats of Qur'an)for them, except that we do not know what of that would agree withyou.' The Messenger of ,Allah, may Allah bless him and grant himpeace, said, 'Make incantations for them. Had anything been able toprecede the decree, the evil eye would precede it.' " Translation Not Available

Book reference: Muwatta Imam Malik Book 50 Hadith 1716
Web reference: Muwatta Imam Malik Book 50 Hadith 3