Musnad Ahmad

Abu Al-Aswad (may Allah have mercy on him) says that once I set out towards Madinah Munawwarah. When I arrived there, I found out that a disease had spread, due to which people were dying in large numbers. I was sitting in the gathering of Sayyiduna Umar (may Allah be pleased with him) when a funeral passed by. The people praised the deceased, and Sayyiduna Umar (may Allah be pleased with him) said: "It has become obligatory." Then a second funeral passed by, and the people praised that deceased as well. Sayyiduna Umar (may Allah be pleased with him) again said: "It has become obligatory." A third funeral passed by, and the people spoke ill of that deceased. Sayyiduna Umar (may Allah be pleased with him) said: "It has become obligatory." Eventually, I asked, "O Leader of the Believers! What has become obligatory?" He replied: "I only said what the Prophet (peace and blessings be upon him) said, that for any Muslim for whom four people testify to his goodness, Paradise becomes obligatory for him." We asked, "What if there are three people?" The Prophet (peace and blessings be upon him) said: "The same ruling applies." We asked about two people, and he (peace and blessings be upon him) said: "The same ruling applies for two." Then we ourselves did not ask about one person.