ANSWER:
It was narrated that al-Baraa’ ibn ‘Aazib said: Prophet (peace and blessings of Allah be upon him) said: “When you go to bed, do wudoo’ as if for prayer, then lie down on your right side, then say:
‘Allahummah aslamtu nafsi ilayk, wa wajahtu wajhi ilayk, wa fawwadtu amri ilayk, wa alja’tu zahri ilayk, raghbatan wa rahbatan ilayk, laa malja’a wa laa manjaa minka illa ilayk. Aamantu bi kitaabik alladhi anzalt, wa bi nabiyyik alladhi arsalt (O Allah, I submit myself to You, I turn my face to You, I delegate my affairs to You and I rely totally on You, out of fear and hope of You. There is no refuge or sanctuary from You except in You. I believe in Your Book which You have revealed and in Your Prophet whom You have sent).’ Then if you die, you will have died on the fitrah, (natural state), so make these the last words you speak.” I repeated [these words] to the Prophet (blessings and peace of Allah be upon him) and when I reached the words “Aamantu bi kitaabik alladhi anzalt (I believe in Your Book which You have revealed)”, I said, “wa bi rasoolika (and in Your Messenger).” He said: “No; ‘wa bi nabiyyika (and in Your Prophet)’.”