Wabanayna fawqakum sabAAan shidada (surah An Naba: 12)

Tafseer Tafheem-ul-Quran by Syed Abu-al-A'la Maududi

(78:12) and built above you seven strong firmaments, *9

Wa banaina fauqakum sab `an shi daada

*9) "Strong" in the sense that their boundaries are so strongly fortified that no change whatever occurs in them, nor does any of the countless stars and planets in the heavens, violating these boundaries, collide with the other, nor falls down to the earth. (For further explanation, see E.N. 34 of Al-Baqarah, E.N. 2 of Ar Ra'd, E.N.'s 8, 12 of Al-Hijr, E.N. 15 of AI-Mu'minun, E.N. 13 of Luqman, E.N. 37 of Ya Sin, E.N.'s 5, 6 of As-Saaffat, E.N. 90 of Al-Mu'min, E.N.'s 7, 8 of Surah Qaf).