To invoke for Allah's Blessings upon the children Sahih al-Bukhari 6354

Arabic hadith text
حَدَّثَنَا عَبْدُ الْعَزِيزِ بْنُ عَبْدِ اللَّهِ، حَدَّثَنَا إِبْرَاهِيمُ بْنُ سَعْدٍ، عَنْ صَالِحِ بْنِ كَيْسَانَ، عَنِ ابْنِ شِهَابٍ، قَالَ أَخْبَرَنِي مَحْمُودُ بْنُ الرَّبِيعِ، وَهُوَ الَّذِيمَجَّ رَسُولُ اللَّهِ صلى الله عليه وسلم فِي وَجْهِهِ وَهْوَ غُلاَمٌ مِنْ بِئْرِهِمْ‏.‏
Translation
Narrated Mahmud bin Ar-Rabi

On whose face Allah's Messenger (ﷺ) had thrown water from his mouth, the water having been taken from their well while he was still a young boy (who has not yet attained the age of puberty).