حَدَّثَنَا يُوسُفُ بْنُ حَمَّادٍ الْمَعْنِيُّ، حَدَّثَنَا عَبْدُ الْوَارِثِ بْنُ سَعِيدٍ، عَنْ عَبْدِ الْعَزِيزِ بْنِ صُهَيْبٍ، عَنْ أَنَسِ بْنِ مَالِكٍ، عَنِ النَّبِيِّ ـ صلى الله عليه وسلم ـ قَالَ ‏"‏ مَا مِنْ مُسْلِمَيْنِ يُتَوَفَّى لَهُمَا ثَلاَثَةٌ مِنَ الْوَلَدِ لَمْ يَبْلُغُوا الْحِنْثَ إِلاَّ أَدْخَلَهُمُ اللَّهُ الْجَنَّةَ بِفَضْلِ رَحْمَةِ اللَّهِ إِيَّاهُمْ ‏"‏ ‏.‏

It wasnarrated from Anas bin Malik that the Prophet (PBUH) said: “Thereare no two Muslims (mother and father), three of whose childrendiebefore reaching the age of puberty, but Allah will admit them toParadise by virtue of His mercy towards them.” Translation Not Available

Book Ref: Sunan Ibn Majah Book 6 Hadith 1605
Web Ref:  Sunan Ibn Majah Vol 1 Book 6 Hadith 1605