Musnad Ahmad 1118:10

Abu Abd al-Rahman narrated to us, Haywah narrated to us, he said: Abu Hani informed me that Abu Ali Amr ibn Malik al-Janbi narrated to him, from Fadalah ibn Ubayd, from the Messenger of Allah, peace and blessings of Allah be upon him, that he said: "Three [types of people], do not ask about them: A man who separated from the community, disobeyed his leader, and died while disobedient; and a slave girl or a male slave who ran away and then died; and a woman whose husband was absent, having provided her with the provisions of the world, yet she displayed her adornment after him—so do not ask about them. And three [types of people], do not ask about them: A man who disputed with Allah regarding His cloak, for His cloak is pride and His lower garment is might; and a man who doubted the command of Allah; and despairing of the mercy of Allah."