Tafsir of Al-Haqqah 69:18

The act of "bringing forth" (al-'ard) in His exalted saying: "On that day you shall be brought (for judgment)" is a metaphor for the Reckoning; the intended meaning is "on that day you shall be held to account." However, it likens that event to a ruler reviewing his army to ascertain their states, and thus it is expressed as such.

Imam Ahmad, ‘Abd ibn Humayd, al-Tirmidhi, Ibn Majah, Ibn Abi Hatim, and Ibn Marduyah recorded on the authority of Abu Musa, who said: The Messenger of Allah (may Allah exalt him and grant him peace) said: "People will be brought forth on the Day of Resurrection in three presentations. As for the first two, they will be arguments and excuses; as for the third, that is when the records fly into their hands, with some taking them in their right hand and others in their left."

The sentence for which the tanwin (in yawma'idhin) is a substitute—according to what their words indicate—is: "The Trumpet is blown," with "On that day you shall be brought" being a substitute for "on that day," and so on. You have already heard that the time frame is expansive enough to encompass all that he mentioned and more.

And His exalted saying: "Not a secret of yours will be hidden" is a circumstantial clause (hal) referring to the active subject in "you shall be brought." That is, you shall be brought while no secret of yours is hidden from Him—the Almighty and Exalted—even before that. The presentation is merely for the public manifestation of one's state, the establishment of proof, and the perfection of justice. Alternatively, it may mean: "not hidden on that day from the people," similar to His exalted saying: "The day when secrets will be put to the test."

Hamzah, al-Kisa'i, Ibn Wathab, Talhah, al-A'mash, and Ibn Miqsam—reporting from ‘Asim and others—read it as la yakhfa (with a ya at the beginning).