Musnad Ahmad 2:282

Muhammad ibn Ja‘far narrated to us, Sa‘id and ‘Abd al-Wahhab narrated to us, from Sa‘id, from Qatadah, from Abu al-‘Aliyah, from Ibn ‘Abbas, that he said: "Men who are pleasing to me bore witness before me, among whom was ‘Umar, and the most pleasing of them to me was ‘Umar: that the Messenger of Allah (peace and blessings of Allah be upon him) forbade prayer after the morning prayer until the sun rises, and after the afternoon (Asr) prayer until it sets."