Musnad Ahmad 30:837

Muhammad ibn Abi ‘Adi narrated to us, from Ibn ‘Awn, from Hilal ibn Abi Zaynab, from Shahr ibn Hawshab, from Abu Hurayrah, that he said: The martyr was mentioned in the presence of the Prophet, peace and blessings of Allah be upon him, and he said: "The earth does not dry from the blood of the martyr until his two wives hasten to him, as if they were two wet nurses who have overshadowed—or lost—their weaned young in an open expanse of land. In the hand of each one of them—or in the hand of each one of them—is a garment better than the world and what is in it."