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