Musnad Ahmad 1304:49

'Arim narrated to us, 'Abdullah ibn al-Mubarak narrated to us, from 'Ubaydullah ibn Abi Ziyad, from Shahr ibn Hawshab, from Asma' bint Yazid, from the Prophet (peace and blessings of Allah be upon him), who said: "Whoever defends the flesh of his brother in his absence, it is a right upon Allah to free him from the Fire."