Sunan Abi Dawud — Jihad (Kitab Al-Jihad) — Hadith No: 2649
Translation
Khabbab said “We came to the Apostle of Allaah(ﷺ) while he was reclining on an outer garment in the shade of the Ka’bah. Complaining to him we said “Do you not ask Allaah for help for us? And do you not pray to Allaah for us? He sat aright turning red in his face and said “A man before you (i.e., in ancient times) was caught and a pit was dug for him in the earth and then a saw was brought placed on his head and it was broken into two pieces but that did not turn him away from his religion. They were combed in iron combs in flesh and sinews above the bones. Even that did not turn them away from their religion. I swear by Allaah, Allaah will accomplish this affair until a rider will travel between San’a and Hadramaut and he will not fear anyone except Allaah, Most High(nor will he fear the attack of) a wolf on his sheep, but you are making haste