Musnad Ahmad 30:2481

Yahya narrated to us, from Abd al-Malik, from Ata, from Abu Hurayrah, from the Prophet, peace and blessings be upon him: "For Allah are one hundred mercies. He sent down from them one mercy between mankind, the jinn, and the crawling creatures. By it, they show affection to one another, and by it, they show mercy to one another, and by it, the wild beast shows affection to its offspring. And He delayed ninety-nine until the Day of Resurrection, by which He will show mercy to His servants."