Children are divided into two categories: children of Muslims and children of nonMuslims. I will start with the children of nonMuslims.
First Category:
In response to a question about the whereabouts of the dead children of nonMuslims, the Prophet ﷺ has given us a concise answer found in both Saheeh Muslim (2659) and Saheeh Al-Bukhari (1383)
حَدَّثَنَا حِبَّانُ، أَخْبَرَنَا عَبْدُ اللَّهِ، أَخْبَرَنَا شُعْبَةُ،
عَنْ أَبِي بِشْرٍ، عَنْ سَعِيدِ بْنِ جُبَيْرٍ، عَنِ ابْنِ عَبَّاسٍ ـ
رضى الله عنهم ـ قَالَ سُئِلَ رَسُولُ اللَّهِ صلى الله عليه وسلم عَنْ
أَوْلاَدِ الْمُشْرِكِينَ فَقَالَ " اللَّهُ إِذْ خَلَقَهُمْ أَعْلَمُ
بِمَا كَانُوا عَامِلِينَ ".
Narrated Ibn `Abbas: Allah's Messenger ﷺ was asked about the children of (Mushrikeen) pagans. The Prophet ﷺ replied, "Since Allah created them, He knows what sort of deeds they would have done." [Sahih al-Bukhari 1383]
Scholars explain this hadeeth stating that they will be tested on the day of Judgment along with three other types of people. They quote the following hadeeth as evidence:
عن أنس قال ، قال رسول الله صلى الله عليه وسلم : "يؤتى بأربعة يوم
القيامة : بالمولود ، والمعتوه ، ومن مات في الفترة ، والشيخ الفاني ،
كلهم يتكلم بحجته ، فيقول الرب تبارك وتعالى لعُنُق من النار : أُبْرزْ ،
ويقول لهم : إني كنت أبعث إلى عبادي رسلا من أنفسهم ، وإني رسول نفسي
إليكم ، اُدخلوا هذه ( أي النار ) ، قال : فيقول من كتب عليه الشقاء : يا
رب أنى ندخلها ومنها كنا نفرّ ، قال : ومن كتب عليه السعادة يمضي فيقتحم
فيها مسرعاً ، قال : فيقول الله تعالى أنتم لرسلي أشد تكذيبا ومعصية ،
فيدخل هؤلاء الجنة وهؤلاء النار" . الراوي : أنس بن مالك | المحدث :
البوصيري | المصدر : إتحاف الخيرة المهرة الصفحة أو الرقم: 8/177 | خلاصة
حكم المحدث : له شاهد
Anas reported that the Messenger of Allah said:
“Four kinds of people will be brought on the Day of Judgment: the
infant, the insane, the one who died during the Fatrah (the period
between two prophets) and the very old man. All of them will speak in
their own defense, then the Lord Almighty and Blessed will say to a
neck of Hell, ‘Come forth’ and He will say to them, ‘I used to send
Messengers to My slaves from amongst themselves. Now I am the
Messenger of Myself to you. Enter this (meaning, the Fire).’ Those who
are decreed to be among the doomed will say, ‘O Lord, how could we
enter it when we are trying to escape it?’ And those who are decreed
to be among the blessed will rush to enter it. And Allah will say:
‘You would have been more disobedient to My Messengers.’ So those (who
obeyed) will enter Paradise and those (who disobeyed) will enter
Hell.” Narrated by Abu Ya3laa, 4224.
Blockquote
Although the above hadeeth has a weakness in its chain of narration, it is strengthened by corroborating reports which were mentioned by Ibn Katheer in his Tafseer.
Thus, we understand that some of the Non-Muslim children will be admitted to Paradise and some of them will be admitted to Hellfire.
Second Category:
As for the dead children of Muslims, the Prophet ﷺ has given his Ummah two great tidings of the mercy of Allah to their parents because of their parents’ belief: not only will they be admitted to Paradise, but they will be allowed to intercede for their parents as well. These are the parents who suffered the loss of their loved ones and were patient and believed in Allah’s reward.
حَدَّثَنَا سُوَيْدُ بْنُ سَعِيدٍ، وَمُحَمَّدُ بْنُ عَبْدِ الأَعْلَى، -
وَتَقَارَبَا فِي اللَّفْظِ - قَالاَ حَدَّثَنَا الْمُعْتَمِرُ، عَنْ
أَبِيهِ، عَنْ أَبِي السَّلِيلِ، عَنْ أَبِي حَسَّانَ، قَالَ قُلْتُ
لأَبِي هُرَيْرَةَ إِنَّهُ قَدْ مَاتَ لِيَ ابْنَانِ فَمَا أَنْتَ
مُحَدِّثِي عَنْ رَسُولِ اللَّهِ صلى الله عليه وسلم بِحَدِيثٍ تُطَيِّبُ
بِهِ أَنْفُسَنَا عَنْ مَوْتَانَا قَالَ قَالَ نَعَمْ " صِغَارُهُمْ
دَعَامِيصُ الْجَنَّةِ يَتَلَقَّى أَحَدُهُمْ أَبَاهُ - أَوْ قَالَ
أَبَوَيْهِ - فَيَأْخُذُ بِثَوْبِهِ - أَوْ قَالَ بِيَدِهِ - كَمَا آخُذُ
أَنَا بِصَنِفَةِ ثَوْبِكَ هَذَا فَلاَ يَتَنَاهَى - أَوْ قَالَ فَلاَ
يَنْتَهِي - حَتَّى يُدْخِلَهُ اللَّهُ وَأَبَاهُ الْجَنَّةَ " .
وَفِي رِوَايَةِ سُوَيْدٍ قَالَ حَدَّثَنَا أَبُو السَّلِيلِ
وَحَدَّثَنِيهِ عُبَيْدُ اللَّهِ بْنُ سَعِيدٍ حَدَّثَنَا يَحْيَى -
يَعْنِي ابْنَ سَعِيدٍ - عَنِ التَّيْمِيِّ بِهَذَا الإِسْنَادِ وَقَالَ
فَهَلْ سَمِعْتَ مِنْ رَسُولِ اللَّهِ صلى الله عليه وسلم شَيْئًا
تُطَيِّبُ بِهِ أَنْفُسَنَا عَنْ مَوْتَانَا قَالَ نَعَمْ .
>
Abu Hassan reported: I said to Abu Huraira that my two children had
died. Would you narrate to me anything from Allah's Messenger ﷺ a
hadith which would soothe our hearts in our bereavements? He said:
Yes. Small children are the fowls of Paradise. If one of them meets
his father (or he said his parents) he would take hold of his cloth,
or he said with his hand as I take hold of the hem of your cloth (with
my hand). And he (the child) would not take off (his hand) from it
until Allah causes his father to enter Paradise. [Sahih Muslim 2635]
This hadith has been narrated on the authority of Tamim with the same
chain of transmitters. And he is reported to have said: Did you hear
from Allah's Messenger ﷺ anything which may soothe our heart in our
bereavements? He said: Yes.
These Muslim children will be joined by the children of the Non-Muslims who will pass the test mentioned in the first category. Indeed, the following hadeeth from Saheeh Al-Bukhari indicates that they were sitting in the company of Ibraheem ﷺ when Prophet Mohamed ﷺ saw them.
حَدَّثَنِي مُؤَمَّلُ بْنُ هِشَامٍ أَبُو هِشَامٍ، حَدَّثَنَا
إِسْمَاعِيلُ بْنُ إِبْرَاهِيمَ، حَدَّثَنَا عَوْفٌ، حَدَّثَنَا أَبُو
رَجَاءٍ، حَدَّثَنَا سَمُرَةُ بْنُ جُنْدَبٍ ـ رضى الله عنه ـ قَالَ
كَانَ رَسُولُ اللَّهِ صلى الله عليه وسلم مِمَّا يُكْثِرُ أَنْ يَقُولَ
لأَصْحَابِهِ " هَلْ رَأَى أَحَدٌ مِنْكُمْ مِنْ رُؤْيَا ". قَالَ
فَيَقُصُّ عَلَيْهِ مَنْ شَاءَ اللَّهُ أَنْ يَقُصَّ، وَإِنَّهُ قَالَ
ذَاتَ غَدَاةٍ " إِنَّهُ أَتَانِي اللَّيْلَةَ آتِيَانِ، وَإِنَّهُمَا
ابْتَعَثَانِي، وَإِنَّهُمَا قَالاَ لِي انْطَلِقْ. وَإِنِّي
انْطَلَقْتُ مَعَهُمَا،فَانْطَلَقْنَا فَأَتَيْنَا عَلَى رَوْضَةٍ
مُعْتَمَّةٍ فِيهَا مِنْ كُلِّ نَوْرِ الرَّبِيعِ، وَإِذَا بَيْنَ
ظَهْرَىِ الرَّوْضَةِ رَجُلٌ طَوِيلٌ لاَ أَكَادُ أَرَى رَأْسَهُ طُولاً
فِي السَّمَاءِ، وَإِذَا حَوْلَ الرَّجُلِ مِنْ أَكْثَرِ وِلْدَانٍ
رَأَيْتُهُمْ قَطُّ ـ قَالَ ـ قُلْتُ لَهُمَا مَا هَذَا مَا هَؤُلاَءِ
قَالَ قَالاَ لِي انْطَلِقِ انْطَلِقْ.وَأَمَّا الرَّجُلُ الطَّوِيلُ
الَّذِي فِي الرَّوْضَةِ فَإِنَّهُ إِبْرَاهِيمُ صلى الله عليه وسلم
وَأَمَّا الْوِلْدَانُ الَّذِينَ حَوْلَهُ فَكُلُّ مَوْلُودٍ مَاتَ عَلَى
الْفِطْرَةِ ". قَالَ فَقَالَ بَعْضُ الْمُسْلِمِينَ يَا رَسُولَ
اللَّهِ وَأَوْلاَدُ الْمُشْرِكِينَ فَقَالَ رَسُولُ اللَّهِ صلى الله
عليه وسلم " وَأَوْلاَدُ الْمُشْرِكِينَ.
Narrated Samura bin Jundub: Allah's Messenger ﷺ very often used to ask
his companions, "Did anyone of you see a dream?" So dreams would be
narrated to him by those whom Allah wished to tell. One morning the
Prophet ﷺ said, "Last night two persons came to me (in a dream) and
woke me up and said to me, 'Proceed!' I set out with them … They said
to me, 'Proceed! Proceed!' So we proceeded till we reached a garden of
deep green dense vegetation, having all sorts of spring colors. In the
midst of the garden there was a very tall man and I could hardly see
his head because of his great height, and around him there were
children in such a large number as I have never seen. I said to my
companions, 'Who is this?' They replied, 'Proceed! Proceed!'… And the
tall man whom you saw in the garden, is Abraham and the children
around him are those children who die with Al-Fitra (the Islamic
Faith). The narrator added: Some Muslims asked the Prophet, "O Allah's
Messenger ﷺ! What about the children of pagans?" The Prophet (ﷺ)
replied, "And also the children of pagans." [Sahih al-Bukhari 7047]
In short, all Muslim children will go to Paradise, and non-Muslim children will be tested, some will go to Paradise, and some will not.