Musannaf Ibn Abi Shaybah

Hazrat Urwah narrates that when the people of Banu Salim began to apostatize, Hazrat Abu Bakr (may Allah be pleased with him) sent Hazrat Khalid bin Walid (may Allah be pleased with him) with an army towards them. There, he gathered the people in one place and set fire to them. When Hazrat Umar (may Allah be pleased with him) learned of this, he came to Hazrat Abu Bakr (may Allah be pleased with him) and said to him that you should remove from leadership such a person who inflicts a punishment that is the right of Allah alone! Hazrat Abu Bakr (may Allah be pleased with him) replied, "By Allah, I cannot sheathe the sword of Allah until Allah Himself sheathes His sword." Then Hazrat Abu Bakr (may Allah be pleased with him) ordered Hazrat Khalid bin Walid (may Allah be pleased with him) to proceed towards Musaylimah.