Musnad Ahmad 1237:2

Ya'qub narrated to us, he said: My father narrated to us, from Ibn Ishaq, he said: Yazid ibn Abi Habib narrated to me, from Khayr ibn Nu'aym al-Hadrami, from Abdullah ibn Hubayrah al-Saba'i—and he was trustworthy—from Abu Tamim, from Abu Basrah al-Ghifari, who said: The Messenger of Allah (peace and blessings of Allah be upon him) led us in the Asr prayer. When he finished, he said: "Indeed, this prayer was presented to those who were before you, but they were negligent regarding it and abandoned it. So whoever among you performs it, his reward shall be doubled for him twice over. And there is no prayer after it until the witness is seen, and the witness is the star."