Is the specification of the term as 'until Al-Mayassara' (the time of ease/ability to pay) valid in a deferred sale?
Chapter on Guaranteed Salaf (Advance Payment) for a Specified Term
Al-Mughni
Book of Sales
Primary text
Specifying the term of the deferred sale as 'until Al-Mayassara' is invalid. Even those who might allow specification by conventionally known but slightly varying times would agree that specifying the term as 'until Al-Mayassara' is invalid.
Supporting text
A narration concerning the Prophet, peace be upon him, sending a message to a Jew to send him two garments 'until Al-Mayassara' is cited. However, Ibn al-Mundhir reported this narration via Huraymi bin 'Umarah, concerning whom Ahmad mentioned carelessness, although noting he was truthful. Ibn al-Mundhir expressed concern that this narration might stem from one of those moments of carelessness, especially since it was not corroborated by other reports. Crucially, there is no dispute that setting the term 'until Al-Mayassara' would render the transaction invalid.