(Al-Infithwar) 82 : 1
بِسْمِ اللَّهِ الرَّحْمَٰنِ الرَّحِيمِ إِذَا السَّمَاءُ انْفَطَرَتْ

When the sky splits asunder.

This verse refers to the terrifying condition of the Last Day. See explanation 81: 11 and 84: 1.