once
لاَ إِلَهَ إِلاَّ اللَّهُ!
Edition transliteration
La ilaha illal-lah.
Meaning
None has the right to be worshipped except Allah.
Source and references
Hisn al-Muslim, entry 245.The reference is copied from the edition; separate editorial verification is not complete yet.
Source edition: Fortress of the Muslim. Open source ↗