وَأَمَّا الْغُلَامُ فَكَانَ أَبَوَاهُ مُؤْمِنَيْنِ فَخَشِينَا أَنْ يُرْهِقَهُمَا طُغْيَانًا وَكُفْرًا ﴿۸۰﴾ فَأَرَدْنَا أَنْ يُبْدِلَهُمَا رَبُّهُمَا خَيْرًا مِنْهُ زَكَاةً وَأَقْرَبَ رُحْمًا ﴿۸۱﴾

﴾80﴿ Wa aammal ghulaamu fakaana abawaahu mu'minaini fakhasheenaaa any yurhiqa humaa tughyaananw wa kufraa
﴾81﴿ Faradnaa any yubdila humaa Rabbuhumaa khairam minhu zakaatanw wa aqraba ruhmaa

﴾80﴿ And as for the young man, his parents were believers, and we feared that he would overwhelm them with rebellion and disbelief
﴾81﴿ So we intended that their Lord would replace him with someone better than him in purity (of faith and conduct) and closer in affection (toward his parents)

[80] The conclusion is that this boy was a rebellious disbeliever, while his mother and father were believers.
There was fear that he would compel his parents, through the dominance of disbelievers and polytheists, to follow disbelief. And there was no longer any hope for him to embrace faith, as proven by the hadith: “The boy whom the companion of Musa killed was created with the nature of a disbeliever.”
This means he was inherently sealed as a disbeliever.
Some hadith commentators have erred in interpreting this hadith. They claim that the boy had become a disbeliever. This interpretation is incorrect, because it contradicts the verse of the Qur’an: “The natural disposition (fiṭrah) upon which Allah has created mankind,” and the hadith: “Every newborn is born upon the fiṭrah.”
This points to the fact that every harmful person should be removed in an appropriate manner so that people may be saved from their harm.
In (ṭughyānan wa kufran) (rebellion and disbelief), both attributes refer to the boy, making them explanatory of the cause (maf‘ūl lahu).
Or, it may refer to the rebellion and disbelief of the parents, meaning lest they fall into rebellion and disbelief—i.e., ʿalā al-ṭughyān wa al-kufr.
[81] This indicates that Allah the Exalted sometimes brings about good in place of evil—that is, the result of removing harm is goodness.
Commentators have mentioned that Allah the Exalted gave the mother and father, in exchange, a daughter who married a prophet, and from that union a son was born who was also a prophet.
And some have said that twelve prophets were born from his lineage.