Tafsir of At-Tur 52:7

The sentence upon which the oath is sworn is His saying, the Exalted: "Indeed, the punishment of your Lord is surely coming to pass."

Meaning: It is certainly occurring with intensity, as if it were prepared in an elevated place, so it descends upon those among the disbelievers who are afflicted by it. In attributing it to the Lord, along with the attribution of the Lord to the pronoun [referring] to him—blessings and peace be upon him—there is a security for him, may the blessings of the Exalted be upon him, and an indication that the punishment will befall those who called him a liar. Zayd ibn Ali, may Allah the Exalted be pleased with both of them, recited "waqi‘" (coming to pass) without the [emphatic] lam. And His saying, the Exalted...