Musnad Ahmad

Abdullah bin Shaqiq (may Allah have mercy on him) says that one day after Asr, Sayyiduna Ibn Abbas (may Allah be pleased with them both) gave us a sermon until the sun set and the stars began to appear. People started calling out, "Prayer, prayer!" At that time, there was also a man from Banu Tamim among the people, and he began to loudly say, "Prayer, prayer!" This made Sayyiduna Ibn Abbas (may Allah be pleased with them both) angry, and he said: "Do you want to teach me the Sunnah? I have seen the Prophet (peace and blessings be upon him) combine (Salat) between Dhuhr and Asr, and between Maghrib and Isha, a 'combining in form' (jam' suwari)." The narrator of the hadith, Abdullah, says that I felt some doubt about this in my heart, so I met Sayyiduna Abu Hurairah (may Allah be pleased with him) and asked him about this issue, and he also agreed with it.