أَعُوْذُ بِاللّٰهِ مِنَ الشَّيْطَانِ الرَّجِيْمِ آمَنْتُ بِاللّٰهِ وَرُسُلِهِ
He should seek refuge in Allaah.
أَعُوْذُ بِاللّٰهِ مِنَ الشَّيْطَانِ الرَّجِيْمِ
I seek refuge in Allah from Satan the outcast.
He should renounce that which is causing such doubt
He should say:
آمَنْتُ بِاللّٰهِ وَرُسُلِهِ
I believe in Allah and His Messenger.
Al Bukhaaree with al-Fath 6/336 and Muslim 1/120
Muslim 1/119,120.