Praise be to Allah.
The scholars are unanimously agreed that the fate of Muslim children -- if they die after the soul has been breathed in and before reaching puberty -- is Paradise, as an honour from Allah, may He be exalted, to them and their parents and as a mercy from Him, Whose mercy encompasses all things.
The texts of the scholars concerning this matter have been quoted in the answer to question number 6496.
By studying the texts which speak of the situation of Muslim children in al-Barzakh and at the time of resurrection and reckoning on the Day of Resurrection, then when entering Paradise, we can divide their journey into the following stages:
Their situation in al-Barzakh. It is proven that as soon as they die they are transferred to Paradise and that their souls are blessed there under the care of our father Ibraaheem (peace be upon him).
This was narrated in the hadeeth of Samurah ibn Jundub (may Allah be pleased with him) who said: The Messenger of Allaah (peace and blessings of Allaah be upon him) often used to say to his companions: “Has anyone among you seen a dream?” and whoever Allaah willed would tell him what he had seen. One day he said: “Last night two people came to me and made me get up, and they said to me: ‘Let’s go.’ So I set off with them…” He mentioned things that he had seen, then he said:
“We set off, and we came to a verdant garden, in which were all the colours of spring, where there was a man who was so tall that I could hardly see his head in the sky. Around the man was the largest number of children I had ever seen…” Then among things that the two angels explained to him was: “As for the tall man who was in the garden, that was Ibraaheem. As for the children who were around him, these are all the children who died in a state of fitrah.” One of the Muslims said: “O Messenger of Allaah, what about the children of the mushrikeen?” He said: “And the children of the mushrikeen.” Narrated by al-Bukhaari (7047).
And it was narrated that Ibn Mas’ood (may Allah be pleased with him) said:
The souls of the children of the believers are in the crops of birds which go wherever they want in Paradise and return to lamps hanging from the Throne. End quote.
Narrated by Ibn Abi Haatim with his isnaad. See Tafseer al-Qur’aan al-‘Azeem, 7/148
For some of the details concerning that on our site, please see the answer to question number 71175.
On the Day of Resurrection, people will be raised from their graves and the children will also be raised in the state of childhood and youth in which they died, and they will intercede for their parents and admit them to Paradise by Allah’s mercy towards them:
It was narrated that Abu Hassaan said: I said to Abu Hurayrah: Two of my sons have died. Can you narrate to me any hadeeth from the Messenger of Allaah (blessings and peace of Allah be upon him) which will console us for our loss? He said: Yes: “Their little ones are the little ones (da’aamees) of Paradise. When one of them meets his father – or his parents – he takes hold of his garment – or his hand – as I am taking told of the hem of your garment, and he does not let go until Allaah admits him and his father to Paradise.”
Narrated by Muslim, 2635
Ibn al-Atheer said: Da’aamees is the plural of da’moos, which refers to a small creature that lives in ponds. Da’moos also refers to the one who wanders about, i.e., they go everywhere in Jannah, entering all places, and they will not be barred from any place, as children in this world are not barred from entering upon women and no one hides away from them. End quote. Al-Nihaayah, 2/279
This hadeeth clearly indicates that the children will remain as children at the time of resurrection, recompense and reckoning, and even the miscarried foetus into whom the soul had been breathed will remain as he was on the day he was miscarried from his mother's womb.
When the people of Paradise enter Paradise and take their places there.
Some scholars are of the opinion that they will all -- old and young alike -- enter Paradise aged thirty-three, and they will not grow old; they will enjoy their youth for ever and ever. Allah will make children grow older and old men grow younger, until they are all the same age, the age that is the prime of youth, thirty-three years.
It was narrated from Mu’aadh ibn Jabal (may Allah be pleased with him) that the Prophet (blessings and peace of Allah be upon him) said:
“The people of Paradise will enter Paradise hairless, beardless with their eyes anointed with kohl, aged thirty or thirty-three years.”
Narrated by al-Tirmidhi, 2545; he said it is hasan ghareeb. It was also narrated by Imam Ahmad in al-Musnad, 2/315, from Abu Hurayrah, and classed as hasan by the commentators. Also narrated by al-Haythami in Majma’ al-Zawaa’id, 10/402; classed as saheeh by Abu Haatim in al-‘Ilal, 3.272 and by al-Albaani in al-Silsilah al-Saheehah, 6/1224.
This was stated clearly in the report of Abu Sa’eed al-Khudri (may Allah be pleased with him) – although its isnaad is subject to some discussion -- according to which the Prophet (blessings and peace of Allah be upon him) said: “Whoever of the people of Paradise dies, young or old, will be aged thirty-three in Paradise and will never grow older, and the same applies to the people of Hell.” Narrated by al-Tirmidhi (2562) who classed it as da’eef, as he said: This is a ghareeb hadeeth which we know only from the hadeeth of Rashdeen – namely Ibn Sa’d. Ibn Ma’een said: He is not trustworthy. Al-Nasaa’i said: He is matrook (i.e., his hadeeth is to be rejected).
Other scholars among the Sahaabah and Taabi’een were of the view that Muslim children who die before reaching the age of puberty will be the servants of the people of Paradise, who will go around among them with drinks and food and other delights; these are the ones who are mentioned in the verses in which Allah says (interpretation of the meaning):
“Immortal boys will go around them (serving),
18. With cups, and jugs, and a glass of flowing wine”
“And there will go round boy‑servants of theirs, to serve them as if they were preserved pearls”
“And round about them will (serve) boys of everlasting youth. If you see them, you would think them scattered pearls”
That was narrated by al-‘Allaamah Ibn al-Qayyim from ‘Ali ibn Abi Taalib (may Allah be pleased with him) and from al-Hasan al-Basri (may Allah have mercy on him), but he favoured the view that these children who will serve the people of Paradise are slaves who are created especially for Paradise, like al-hoor al-‘iyn, and that they are something other then the children of Muslims who die in this world. He said: As for the children of people in this world, on the Day of Resurrection they will be 33 years old. End quote.
See: Haadi al-Arwaah ila Bilaad al-Ifraah, p. 309-311
Perhaps the second opinion is the more correct view concerning this matter, because of the hadeeth of Abu Hurayrah quoted above, in which it says: “Their little ones are the little ones of Paradise.” This is more sound and more correct than the view of the other scholars.
Al-Manaawi (may Allah have mercy on him) said:
Meaning: they wander around in Paradise and enter its houses, and they are not prevented from doing so just as children in this world are not prevented from entering even private places.
And it was said that al-da’moos refers to the man who frequently visits kings, because such people frequently come in and go out, and they do not wait for permission and do not care where they go in their houses. The child of Paradise is likened to him because he goes wherever he wants in Paradise and is not kept out of any part of it. End quote. Fayd al-Qadeer, 4/194; something similar was stated in Mirqaat al-Mafaateeh by Mulla ‘Ali al-Qaari 4/16.
See also the answer to question number 20469
And Allah knows best.