Musnad Ahmad 1017:23

Isma'il ibn Ibrahim narrated to us, Hisham al-Dastawa'i informed us, Yahya ibn Abi Kathir narrated to us, from Abu Qilabah, from Abu al-Malih, who said: We were with Buraydah on a military expedition on a cloudy day. He said: "Perform the prayer early, for the Messenger of Allah, peace and blessings of Allah be upon him, said: 'Whoever leaves the Asr prayer, his deeds are rendered void.'"