Musnad Ahmad 1156:175

Isma'il narrated to us, Ibn Jurayj narrated to us, from Abdullah ibn Abi Mulaykah, he said: Umm Salamah said: "The Messenger of Allah, peace and blessings of Allah be upon him, was more hasty in performing the Dhuhr prayer than you are. And you are more hasty in performing the Asr prayer than he was."