فَأَرَدنا أَن يُبدِلَهُما رَبُّهُما خَيرًا مِنهُ زَكاةً وَأَقرَبَ رُحمًا

So We desired that their Lord should give them in exchange one better than him in respect of purity and closer in mercy.

EXEGESIS

Yubdilahumā (give them in exchange) is a conjugate of abdala, meaning to exchange, plus the object. It is said that abdala (the fourth verb form) differs from baddala (the second verb form) in the sense that tabdīl (the second form) is to change the nature of something, whilst ibdāl (the fourth form) is to exchange it by taking something away and putting something else in its stead.^{‎[1]Baghawi, 3/210.}

Zakāh (purity) means pure, purity, innocence, and free from blemishes and sins. In this verse, zakātan is the specifying accusative (tamyīz) for khayran minhu, as ruḥman is the same for aqrabu.

Ruḥm (mercy) comes from raḥmah meaning mercy. Although some have suggested it comes from raḥim meaning close family.^{‎[2]Tibyan, 7/81; Tabari, 16/4-5; Thalabi, 66/187; Mizan, 13/348. Ṭabarī rejects the meaning of raḥim for this reason, saying that both the child killed and the child that was to be born came from the same mother and father and therefore could not be said to be closer in kinship (raḥim). Thaʿlabī and Tabatabai on the other hand prefer the meaning of raḥim. Tabatabai’s reasoning for this preference is that aqrabu (closer) is not appropriate to be used in conjunction with ruḥm in the meaning of mercy; if that were the case, he says it should be akthara (more).}

In any case, the usage of ruḥm and aqrab (which calls to mind aqārib/qurbā, meaning family members) is undoubtedly a play on words, illustrating that the new child was more akin to the parents – in character and faith – than the previous. In other words, more suited to be called their child.

EXPOSITION

This verse explicates that the killing of the child was undertaken for the benefit of the parents, who were faithful.^{‎[3]Tibyan, 7/81.}

That their Lord: the pronoun their (dual) shows God’s love and attention He paid to the believing parents.

Should give them in exchange: the dual them is used here, referring to the parents, clarifying that all this was done for their sake.

One better than him in respect of purity: He wished to give them instead of the rebellious and faithless child a better one, more suited for such good parents: better in faith, religiosity, and character.^{‎[4]Tabrisi, 6/753; Tabari, 16/4; Mizan, 13/348.} The word purity (zakāh) is here meant to be juxtaposed with Moses’ (a) objection, Did you slay an innocent (zakiyyah) soul (verse 74), as if to say: Yes, the child that I killed was a pure and innocent soul but God knew what would become of him and wished to give one that would be better in purity, because it would remain in purity and help keep the parents in purity too.^{‎[5]Razi, 21/491; Nemuneh, 12/504.}

And closer in mercy: meaning better for the parents and more merciful towards them than the one killed.^{‎[6]Tibyan, 7/81; Tabari, 16/4.} Another suggestion is that it means the parents loved the new child more because of his/her better character and nature.^{‎[7]Alusi, 8/334.}

We may also note that purity and closer in mercy are juxtaposed to rebellion and unfaith of the previous verse.^{‎[8]Mudarrisi, 6/463.}

INSIGHTS FROM HADITH

1. Ṭabrisī says it is reported from Imam al-Ṣādiq (a) that the parents were given a daughter from whose progeny came seventy prophets.^{‎[9]Ayyashi, 2/336; Tabrisi, 6/753. See also Qummi, 2/40, where this is attributed to Imam al-Riḍā (a). This is also reported from Imam al-Ṣādiq (a) by Thalabi, 6/187, and Baghawi, 3/210. It has been mentioned without the attribution in Zamakhshari, 2/741. Qurṭubī attributes to Qatādah that the number is twelve prophets (Qurtubi, 11/37). Qurṭubī also relates the number seventy from Imam al-Ṣādiq (a) and then adds: ‘Our scholars say this is unlikely, and it is not known that anyone but the Banī Isrāʾīl should have so many prophets.’ He adds that the woman was most evidently not from Banī Isrāʾīl (see also Andulusi, 3/536). In any case this criticism is obviously not very convincing (see Alusi, 8/335).} The fact that she was a girl has been mentioned by many others as well.^{‎[10]See for example Tabari, 16/4, although he also reports the opinion that it was a boy.} Another claim is that she married a prophet.^{‎[11]Tabrisi, 6/753; Thalabi, 6/187; Zamakhshari, 2/741.}

[1] Baghawi, 3/210.
[2] Tibyan, 7/81; Tabari, 16/4-5; Thalabi, 66/187; Mizan, 13/348. Ṭabarī rejects the meaning of raḥim for this reason, saying that both the child killed and the child that was to be born came from the same mother and father and therefore could not be said to be closer in kinship (raḥim). Thaʿlabī and Tabatabai on the other hand prefer the meaning of raḥim. Tabatabai’s reasoning for this preference is that aqrabu (closer) is not appropriate to be used in conjunction with ruḥm in the meaning of mercy; if that were the case, he says it should be akthara (more).
[3] Tibyan, 7/81.
[4] Tabrisi, 6/753; Tabari, 16/4; Mizan, 13/348.
[5] Razi, 21/491; Nemuneh, 12/504.
[6] Tibyan, 7/81; Tabari, 16/4.
[7] Alusi, 8/334.
[8] Mudarrisi, 6/463.
[9] Ayyashi, 2/336; Tabrisi, 6/753. See also Qummi, 2/40, where this is attributed to Imam al-Riḍā (a). This is also reported from Imam al-Ṣādiq (a) by Thalabi, 6/187, and Baghawi, 3/210. It has been mentioned without the attribution in Zamakhshari, 2/741. Qurṭubī attributes to Qatādah that the number is twelve prophets (Qurtubi, 11/37). Qurṭubī also relates the number seventy from Imam al-Ṣādiq (a) and then adds: ‘Our scholars say this is unlikely, and it is not known that anyone but the Banī Isrāʾīl should have so many prophets.’ He adds that the woman was most evidently not from Banī Isrāʾīl (see also Andulusi, 3/536). In any case this criticism is obviously not very convincing (see Alusi, 8/335).
[10] See for example Tabari, 16/4, although he also reports the opinion that it was a boy.
[11] Tabrisi, 6/753; Thalabi, 6/187; Zamakhshari, 2/741.