“Indeed, it is from Sulayman, and indeed, it reads: In the name of Allah, the Entirely Merciful, the Especially Merciful.”
The letter from Sulayman to the Queen of Sheba (Bilqis), the only place in the Quran where the Basmala appears as part of a narrative rather than as a chapter heading. This indicates the Basmala is a mark of divine letters and sacred correspondence.