کَلَّاۤ اِذَا دُکَّتِ الْاَرْضُ دَکًّا دَکًّا ﴿ۙ۲۱﴾

Most certainly – when the earth is smashed and blown to bits.

Tafsir al-Jalalain                                                                                                                        تفسیر الجلالین                                                

{كَلَّا} رَدْع لَهُمْ عَنْ ذَلِكَ {إِذَا دُكَّتْ الْأَرْض دَكًّا دَكًّا} زُلْزِلَتْ حَتَّى يَنْهَدِم كُلّ بِنَاء عَلَيْهَا وَيَنْعَدِم

No indeed! — a deterrent for them from such [conduct]. When the earth is pulverized repeatedly, when it is shaken until every edifice has collapsed and is destroyed,

Tafsir al-Jalalain of Imam Jalaaluddin Muhammad ibn Ahmad al-Mahalli al-Shafe’i t D. 864 A.H. and Imam Jalaaluddin Abd al-Rahman ibn Abi Bakr al-Suyooti al-Shafe’i t D. 911 A.H.