Sahih al-Bukhari
For the Protection of Children

أُعِوذُ كُمَا بِكَلِمَاتِ اللَّهِ التَّامَّةِ مِنْ كُلِّ شَيْطَانِ وَ هَامَّةِ ، وَ مِنْ كُلِّ عَيْنٍ لامَّةٍ

U’idhukuma bikalimatil lahit-tammah, min kulli shaytanin wahammah, wa min kulli ‘ayinin lammah

(I seek refuge for you in the perfect words of Allah, from every devil and every poisonous reptile, and from every bad eye)

Muhammad (salAllahu alayhi wasalam) would seek protection for his grandsons; Hassan and Hussain (radiAllahu anhum) by the above du’a