in the language of the Quran and elsewhere, with indeclinable nouns, as in His words:

“For his parents (abawayhi), each receives a sixth of what he leaves.”

Then He says:

“But if he has no child and his parents (abawāhu) inherit from him, his mother receives a third.”

He also says:

“And he raised his parents (abawayhi) upon the throne.”

And:

“And wipe your heads and wash your feet up to the ankles (al-ka‘bayni).”

He did not say al-ka‘bāni. He also says:

“And present to them the example of the people of the town, when the messengers came to it: when We sent two (ithnayni) to them, but they denied them both, so We strengthened them with a third.”

He did not say ithnāni. He also says:

“We said, ‘Load aboard it a pair of every kind, two (zawjayni ithnayni) of each.’”

And He says:

“Eight mates: two sheep (ithnayni) and two goats (ithnayni). Say, ‘Has He forbidden the two males (al-dhakarayni), or the two females (al-unthayayni), or what the wombs of the two females (al-unthayayni) contain?’”

He did not say ithnāni, al-dhakarāni, or al-unthayāni. He also says:

“And of everything We created pairs (zawjayni).”

He did not say zawjāni. And He says:

“But if they are females, more than two (ithnatayni)…”

He did not say ithnatāni. Examples of this are numerous and well known, both in the Quran and elsewhere. The grammarians therefore supposed that indeclinable nouns with context-dependent referents, such as hādhayni (these two) and alladhayni (the two who), followed this same pattern, and that an indeclinable form would take an alif in the nominative case. This is where the difficulty arose.

Abū ‘Amr was an authority on Arabic, so he recited according to the Arabic usage he knew: Inna hādhayni la-sāhirāni (“These two are certainly magicians”). He mentioned that he had predecessors in this reading, and this is what one should presume