It was also said: None will intercede except one who testifies that there is no deity but Allah; that is, none will intercede except a believer. (1)
“They say, ‘The Most Merciful has taken a son.’ (88) You have indeed made an outrageous claim. (89) The heavens almost rupture because of it, the earth splits open, and the mountains collapse in ruin.” (90)
“They say, ‘The Most Merciful has taken a son’”: this refers to the Jews, the Christians, and those who claim that the angels are Allah’s daughters.
Hamzah and al-Kisa’i recited wuldan, with an u-vowel on the initial wāw and no vowel on the lām, here, in Surah al-Zukhruf, and in Surah Nuh. Ibn Kathir, Abu Amr, and Yaqub agreed with them in Surah Nuh. The remaining reciters read it waladan, with an a-vowel on both the wāw and the lām. Both are dialectal variants, like al-ʿarab and al-ʿurb, and al-ʿajam and al-ʿujm.
“You have indeed made an outrageous claim”: Ibn Abbas said: an abominable claim. Qatadah and Mujahid said: a grave claim. Muqatil said: You have spoken a grave statement. In Arabic usage, idd denotes the greatest of calamities. (2)
“The heavens almost”: Nafiʿ recited yakādu, with the masculine prefix, here and in Surah Ha Mim Ayn Sin Qaf, because the verb precedes its subject. The remaining reciters read it with the feminine prefix, in consideration of the feminine gender of “the heavens.”
“Rupture because of it”: here and in Surah Ha Mim Ayn Sin Qaf, Abu Amr, Abu Bakr, and Yaqub recited yanfaṭirna, with the n-form derived from infiṭār (splitting apart). Ibn Amir and Hamzah agreed with them here, in view of Allah’s saying: “When the heaven is split open” (al-Infitar: 1), and, “The heaven will be split open thereby” (al-Muzzammil: 18). The remaining reciters read yatafaṭṭarna, with the t-form derived from tafaṭṭur (breaking apart). Both have the same meaning: infaṭara and tafaṭṭara mean “to split open.”
“And the earth splits open, and the mountains collapse in ruin”: that is, they will be shattered completely.
It was also said: “And the earth splits open” means that it will cave in with them. As for the splitting of the sky, it means that it will fall upon them; and “the mountains collapse in ruin” means that they will crash down upon them.