Musannaf Ibn Abi Shaybah

It is narrated from Hazrat Aisha (may Allah be pleased with her) that when Hazrat Abu Bakr Siddiq (may Allah be pleased with him) was near his death, he said: Look into my wealth and see how much it has increased after I assumed the caliphate, and send it to the caliph after me. Indeed, I considered it lawful, and as much wealth as I earned through trade, I have animals of approximately the same value with me. Aisha (may Allah be pleased with her) says that when we looked, there was a Nubian slave (that is, one whose eyes were not sound and who could not see properly) who was carrying his children, and there was a she-camel on which water used to be brought. Aisha (may Allah be pleased with her) says that we sent all this to Umar (may Allah be pleased with him). Aisha (may Allah be pleased with her) says that my grandfather told me that Umar (may Allah be pleased with him) began to weep and said: May Allah have mercy on Abu Bakr, he has put those who come after him into hardship.