Sayyiduna Khabbab (may Allah be pleased with him) said: I came to the Messenger of Allah (peace and blessings be upon him) while he (peace and blessings be upon him) was lying under a tree with his hand placed under his head. I said: O Messenger of Allah! Will you not pray to Allah against these people, whom we fear will turn us away from our religion? He (peace and blessings be upon him) turned his face away from me; I turned towards him again, and he (peace and blessings be upon him) turned his face away from me three times. Each time I said this to him (peace and blessings be upon him), and he (peace and blessings be upon him) turned his face away. The third time he (peace and blessings be upon him) sat up and said: "O people! Fear Allah. By Allah! A man from among the believers before you would have a saw placed on his head and be split into two pieces, yet he would not turn back from his religion. Fear Allah, for Allah, the Mighty and Majestic, will grant you victory and will accomplish (your affair)."
Hadith Referenceالمعجم الكبير للطبراني / باب الخاء / 3633