Sayyiduna Abu Umamah (may Allah be pleased with him) narrates from Sayyiduna Khalid bin al-Walid (may Allah be pleased with him) that he mentioned to the Messenger of Allah (peace and blessings be upon him) the terrifying visions he used to see at night, because of which he could not offer the night prayer. So the Messenger of Allah (peace and blessings be upon him) said: "O Khalid bin al-Walid, shall I not teach you words which you will not have said three times before Allah Almighty removes that state from you?" He said: "Of course, O Messenger of Allah, may my father and mother be ransomed for you; I complained to you about this only in the hope of this." He (peace and blessings be upon him) said: "Say: 'A'udhu bi kalimatillahit-tammati min ghadabihi wa iqabihi wa sharri ibadihi wa min hamazatish-shayatini wa an yahdurun' (I seek refuge in the perfect words of Allah from His anger, His punishment, the evil of His servants, the whisperings of the devils, and from their coming to me)."
The Mother of the Believers, Sayyidah Aishah (may Allah be pleased with her), said: Only a few nights had passed when Sayyiduna Khalid bin al-Walid (may Allah be pleased with him) came and said: "O Messenger of Allah, may my father and mother be ransomed for you, by the One who sent you with the truth, I had not yet completed three times the words you taught me before Allah Almighty removed from me what I used to feel. Now I would not care even if I entered a lion's cage at night."
Hadith Referenceالمعجم الأوسط / باب الألف / 931
Hadith Gradingمحدثین:إسناده ضعيف جدًّا، فيه الحكم بن عبد الله الأيلي متروك
Hadith Takhrij«قال الهيثمي: وفيه الحكم بن عبد الله الأيلي وهو متروك «مجمع الزوائد ومنبع الفوائد، ج 10، ص 127»» «أخرجه مالك فى «الموطأ» برقم: 3499 / 757، وابن حجر فى «المطالب العالية» برقم: 3364»