Sahih Muslim Book 41, Hadith Number 6886.
Harith b Abi Rabi’a and ‘Abdullah b. Safwan both went to Umm Salama, the Mother of the Faithful, and they asked her about the army which would be sunk in the earth, and this relates to the time when Ibn Zubair (was the governor of Mecca). She reported that Allah’s Messenger (may peace be upon him) had said that a seeker of refuge would seek refuge in the Sacred House and an army would be sent to him (in order to kill him) and when it would enter a plain ground, it would be made to sink. I said: Allah’s Messenger, what about him who would be made to accompany this army willy nilly? Thereupon he said: He would be made to sink along with them but he would be raised on the Day of Resurrection on the basis of his intention. Abu Ja’far said: This plain ground means the plain ground of Medina.