Ṭāhā 20:71

Qāla āmantum lahu qabla an ādhana lakum, innahu la-kabīrukumu'lladhī ʿallamakumu's-siḥr, fa-la-uqaṭṭiʿanna aydiyakum wa arjulakum min khilāfin wa la-uṣallibannakum fī judhūʿi'n-nakhli wa la-taʿlamunna ayyunā ashaddu ʿadhāban wa abqā

"He said: 'You have believed him before I gave you leave! He is surely your chief, the one who taught you sorcery. I shall cut off your hands and your feet on alternate sides, and I shall crucify you on the trunks of palm trees, and you shall certainly know which of us is more severe in punishment and more lasting!'"

This sentence was treated in detail at al-Shuʿarāʾ on 26/49, and what was recorded there is not repeated here:

• Qabla an ādhana lakum — "the claim covers not being worshipped but the authority to decide who may believe in what."
• Āmantum lahu — not bihi but lahu: not "you believed in God" but "you put your trust in him" — pulling the matter onto a person.
• Kabīrukumu'lladhī ʿallamakumu's-siḥr — explaining the event as a conspiracy; and the inconsistency of the explanation within the text (the sorcerers had only just been assembled, and Moses had not been in Egypt for years).
• Min khilāf — on alternate sides: the right hand with the left foot.
• And a note of principle: the verse is not laying down a penal ruling; it is transmitting the words of a tyrant. No legal ruling is derived.

I rely on that treatment.

One — the place of the crucifixion is specified: fī judhūʿi'n-nakhl — "on the trunks of palm trees". In al-Shuʿarāʾ there was only la-uṣallibannakum.

Two — and this is the real difference: the threat ends with a sentence of contest.

Wa la-taʿlamunna ayyunā ashaddu ʿadhāban wa abqā — "you shall know which of us is more severe in punishment and more lasting."

A point of word order must be recorded: ayyunā — "which of us". That is, Pharaoh puts himself and the other side into the same sentence, as the two terms of the same measure.

I record this as my own reading, and its ground is that the pronoun is plural: the sentence sets up a comparison between two punishments. That is, Pharaoh tacitly grants in his own sentence the existence of God's punishment and disputes only its degree.

And the word abqā occurs here for the first time. As was tabulated in the section on structure, this word occurs four times in the sūra, and the first is in this verse. In the next verse the sorcerers will answer with the same word.