once
((يَقُولُ: ((آمَنْتُ بِاللَّهِ وَرُسُلِهِ)).
Edition transliteration
He should say: ( Amantu billahi warusulih.)
Meaning
He should say: (I have believed in Allah and His Messenger.)
Source and references
Hisn al-Muslim, entry 134.The reference is copied from the edition; separate editorial verification is not complete yet.
Source edition: Fortress of the Muslim. Open source ↗