Sayyiduna Husayn bin Awf (may Allah be pleased with him) says: When Sayyiduna Umar (may Allah be pleased with him) was informed of the killing of Sayyiduna al-Nu'man bin Muqarrin (may Allah be pleased with him), and it was said that some other people whom we do not know had also been harmed, Sayyiduna Umar (may Allah be pleased with him) said: Allah knows them. Then Husayn bin Awf (may Allah be pleased with him) said: A man sold his life. A man from Ahmas, who was called Malik bin Awf (may Allah be pleased with him), said: He is my maternal uncle, O Commander of the Believers! People think that he threw himself into destruction. Sayyiduna Umar (may Allah be pleased with him) said: The people are wrong; rather, these are the ones who purchased the Hereafter in exchange for the world. Qays says: The one killed was Awf bin Abi Humayd (may Allah be pleased with him), and he is Abu Shibl. And Ya'qub says: Malik is more likely.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب السير / 17929