Are the children of Muslims in Paradise, and what is the meaning of the hadith of Aisha in which the Prophet (peace and blessings be upon him) said, “Allah knows best what they were doing,” regarding a child who died?

Question:
Shaykh, there is a hadith about the children of Muslims being in Paradise, and a hadith of Aisha in which the Prophet (peace and blessings be upon him) said, “Allah knows best what they were doing,” regarding a child. She said, “Congratulations to him, a bird from the birds of Paradise, and a sparrow from the sparrows of Paradise.” How do you reconcile these two?

Answer:
The children of Muslims follow the Muslims in this world and have the rulings of their parents in Islam. Likewise, the children of disbelievers follow their parents in this world, and they are disbelievers and are treated as disbelievers. As for the Hereafter, their affair is up to Allah (Glorified and Exalted is He). The scholars have differed on this matter, and perhaps the closest opinion is that they will be tested on the Day of Resurrection by a messenger being sent to them to call them to Allah. Whoever responds will enter Paradise, and whoever does not respond will enter the Fire.