Ma'arif al-Qur'an
Mufti Muhammad Shafiتَشَقَّقُ السَّمَاءُ بِالْغَمَامِ (The sky will break open with a cloud - 25:25). The explanation of the verse is that the sky will rip apart and a sort of liquid cloud will descend from it which will be carrying angels with it. This cloud will look like a canopy descending from the sky and will be bearing Allah Ta’ ala's refulgence surrounded by angels. This will precede the beginning of the reckoning and the sky will rip open only to make an opening. It will not be the same ripping as the one when the sur (صُور) will be blown to finish off the earth and the sky, because this descension of the cloud will take place after the second blowing of the sur (صُور) when the earth and the sky would have taken the new shape. (Bayan u1-Qur’ an)