What is the interpretation and authenticity of the Hadith: "Indeed, a man may do the deeds of the people of Paradise, as it appears to people, while he is one of the people of the Fire; and indeed, a man may do the deeds of the people of the Fire, as it appears to people, while he is one of the people of Paradise"?

The summary of the answer: The Hadith (definition) states that a man and a woman may perform acts of obedience to Allah for sixty years, then death overtakes them, and they cause harm in their will, thus making Hellfire obligatory for them. This is supported by the Quranic verse: ﴿بعد وصية يوصى بها أو دين غير مضار وصية من الله﴾ [An-Nisa:12].

It was also narrated with another wording that a man may do the deeds of the people of good for seventy years, but if he acts unjustly in his will, his life is concluded with his worst deed, and he enters Hellfire. The reverse is true for one who does the deeds of the people of evil, then acts justly in his will, so his life is concluded with his best deed, and he enters Paradise.

Al-Albani deemed this Hadith weak due to Shahr bin Hawshab, despite some imams having authenticated him.

The interpretation of "they cause harm in their will" means causing harm to the heirs by bequeathing more than one-third to an outsider, or disinheriting some heirs, which is considered detestable and an attempt to evade Allah's ruling.