In this reading, the first word is understood to comprise an + lā, so the verb is subjunctive, referring to the people of Sheba.
أَلَا يَا اسْجُدُوا
alā ya-sjudū
“Listen all, prostrate to God!”
This reading is based on taking alā as an address (by the hoopoe to those assembled), followed by a vocative yā and an imperative verb (usjudū). It is also possible that this is a divine exhortation, separate from the story itself.
Explanation
These readings provide different angles to the story, in which the hoopoe is explaining the situation he encountered in Sheba. The rest of this ayah contains a strong exhortation to worship Allah alone [Makki]. Note that these readings are based on the same orthography, though the second infers two additional alifs.
He has revealed to you ˹O Prophet˺ the Book in truth, confirming what came before it, as He revealed the Torah and the Gospel
Explanation
These readings provide different angles to the story, in which the hoopoe is explaining the situation he encountered in Sheba. The rest of this ayah contains a strong exhortation to worship Allah alone [Makki]. Note that these readings are based on the same orthography, though the second infers two additional alifs.