Sayyiduna Hudhayfah (may Allah be pleased with him) said that the Messenger of Allah (peace and blessings be upon him) said: "After me, follow Abu Bakr and Umar (may Allah be pleased with them both), adopt the way of Ammar (may Allah be pleased with him), and hold fast to the covenant of Ibn Umm Abd (may Allah be pleased with him)."
Hadith Referenceالسنن الكبرى للبيهقي / كتاب قتال أهل البغي / 16590