For a child who died, in the funeral prayer
For a child who died, in the funeral prayer: 2 supplications in Arabic with English translation and sources, from the Fortress of the Muslim (Hisn al-Muslim).
الدعاء للفرط في الصلاة عليه
اللَّهُمَّ أَعِذْهُ مِنْ عَذَابِ القَبْرِ وإن قال: اللَّهُمَّ اجْعَلْهُ فَرَطاً وَذُخْراً لِوَالِدَيْهِ، وَشَفِيعاً مُجَاباً، اللَّهُمَّ ثَقِّلْ بِهِ مَوَازِينَهُمَا، وَأَعْظِمْ بِهِ أُجورَهُمَا، وَأَلْحِقْهُ بِصَالِحِ الْمُؤْمِنِينَ، وَاجْعَلْهُ فِي كَفَالَةِ إِبْرَاهِيمَ، وَقِهِ بِرَحْمَتِكَ عَذَابَ الْجَحِيمِ، وَأَبْدِلْهُ دَاراً خَيْراً مِنْ دَارِهِ، وَأَهْلاً خَيْراً مِنْ أَهْلِهِ، اللَّهُمَّ اغْفِرْ لِأَسْلاَفِنَا، وَأَفْرَاطِنَا، وَمَنْ سَبَقَنَا بِالْإِيمَانِ إن قال ذلك فَحَسَنٌ.
O Allah, protect him from the punishment of the grave. [It is also good to say:] O Allah, make him a forerunner and a treasure for his parents, an intercessor whose plea is answered. O Allah, make their scales heavy through him, increase their reward through him, join him with the righteous believers, place him in the care of Ibrahim, protect him by Your mercy from the punishment of Hell, give him in exchange a home better than his home and a family better than his family. O Allah, forgive those who went before us, our children who died before us and those who preceded us in faith.
اللَّهُمَّ اجْعَلْهُ لَنَا فَرَطاً، وَسَلَفاً، وَأَجْراً.
O Allah, make him for us a forerunner, a predecessor and a reward.
Fortress of the Muslim (Hisn al-Muslim), Sa‘id ibn ‘Ali al-Qahtani. MushafPlus translation made from the Arabic, not reviewed by a specialist.