Sahih al-Bukhari 52:7

Once I went to Medina where there was an outbreak of disease and the people were dying rapidly. I was sitting with `Umar and a funeral procession passed by. The people praised the deceased. `Umar said, "It has been affirmed" (Paradise). Then another funeral procession passed by. The people praised the deceased. `Umar said, "It has been affirmed." (Paradise). Then another funeral procession passed by. The people praised the deceased. `Umar said, "It has been affirmed (Paradise)." Then a third funeral procession passed by and the people talked badly of the deceased. `Umar said, "It has been affirmed (Hell)." I asked `Umar, "O chief of the believers! What has been affirmed?" He said, "I have said what the Prophet (ﷺ) said. He said, 'Allah will admit into paradise any Muslim whose good character is attested by four persons.' We asked the Prophet, 'If there were three witnesses only?' He said, 'Even three.' We asked, 'If there were two only?' He said, 'Even two.' But we did not ask him about one witness."