“acceptable,” as stated above—that is, when corroborated, as he explicitly noted in the introduction; otherwise, his hadith is weak. But it has not been corroborated, as you have seen, so declaring the hadith authentic in this case is likewise mistaken. And Allah knows best.
Add to this that the addition, “three times,” does not occur in the two authentic hadiths: the hadith of al-Baraʾ and that of Hudhayfah. This makes clear that Shaykh ʿAbd al-Qadir al-Arnaʾut’s statement in his commentary on al-Wabil al-Sayyib (p. 127), “It is an authentic hadith,” is incorrect. He often makes such statements concerning certain hadiths, either through misconception or imitation. And Allah knows best.
Note: This supplication—“O Allah, protect me…”—is reported in Sahih Muslim and elsewhere through Thabit ibn ʿUbayd, from ʿUbayd ibn al-Baraʾ, from al-Baraʾ, with the wording: “Whenever we prayed behind the Messenger of Allah (peace and blessings be upon him), we liked to be on his right, so that he would turn his face toward us.” He said: “I heard him saying: ‘My Lord, protect me from Your punishment on the Day You resurrect—or gather—Your servants.’”
This ʿUbayd is not well known. Indeed, when al-Bukhari mentioned him in al-Tarikh al-Kabir (3/1/443), he added nothing beyond the words, “From his father!” The same is found in al-Jarh wa al-Taʿdil (2/2/402), except that it says, “Muharib ibn Dithar narrated from him.” Nor did al-Tahdhib add anyone besides this Thabit ibn ʿUbayd, and it did not report any accreditation of him from