Sayyiduna al-Bara' bin Azib (may Allah be pleased with him) says: "The Messenger of Allah (peace and blessings be upon him) ordered us to follow funerals (that is, to take part in them)."
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الجنائز / Q6616
It is narrated from Sayyiduna Abu Hurayrah (may Allah be pleased with him): I heard the Messenger of Allah (peace and blessings be upon him) say: "The Muslim has five rights over the Muslim: returning the greeting of salam, visiting the sick, following funerals, accepting an invitation, and responding to one who sneezes."
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الجنائز / 6616
Umar bin Ya'la bin Murrah narrates from his father, Sayyiduna Ya'la bin Murrah (may Allah be pleased with him), that he said: I travelled with the Messenger of Allah (peace and blessings be upon him) many times. I never saw him (peace and blessings be upon him) pass by the corpse of a human being without ordering that it be buried. He (peace and blessings be upon him) would not even ask whether it was a Muslim or a disbeliever.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الجنائز / 6617
Umar bin Abdullah narrates from his father that he said: I heard Sayyiduna Ya'la bin Murrah (may Allah be pleased with him), and he narrated a similar hadith.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الجنائز / 6618
It is narrated from Sayyiduna Abdullah bin Umar (may Allah be pleased with them both) that the people were returning from Hajj when they found a dead woman at al-Bayda'. They kept passing by her and no one raised his head to look at her, until a man from Banu Layth called Kulayb the poor passed by. He threw his cloth over her, then called for help from those who would bury her. Sayyiduna Umar (may Allah be pleased with him) called Sayyiduna Abdullah (may Allah be pleased with them both), that is, his son, and said: "Did you pass by this dead woman?" Sayyiduna Abdullah (may Allah be pleased with them both) said: "No." Sayyiduna Umar (may Allah be pleased with him) said: "Had I come to know that you passed by there, I would certainly have punished you." Then Sayyiduna Umar (may Allah be pleased with him) stood among the people, was very angry with them, and said: "Perhaps Allah Almighty will admit Kulayb into Paradise because of this very deed." Once, while Kulayb was performing ablution near the mosque, Abu Lu'lu'ah, the killer of Sayyiduna Umar (may Allah be pleased with him), came to him and ripped open his stomach. Nafi' says: Along with Sayyiduna Umar (may Allah be pleased with him), Abu Lu'lu'ah killed seven people.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الجنائز / 6619