once
بِسْمِ اللَّهِ وَعَلَى سُنَّةِ رَسُولِ اللَّهِ
Edition transliteration
Bismil-lahi waAAala sunnati rasoolil-lah.
Meaning
In the name of Allah and upon the sunnah of the Messenger of Allah.
Source and references
Hisn al-Muslim, entry 163.The reference is copied from the edition; separate editorial verification is not complete yet.
Source edition: Fortress of the Muslim. Open source ↗