Permissible Time Length

4. Muhammad has narrated from Ahmad ibn Muhammad from Muhammad ibn Khalid from Khalaf ibn Hammad who has said the following: “I once sent (a message) to abu al-Hassan عليه السلام, and asked, ‘How much is the minimum duration of time in al-Mut‘ah (advantageous marriage) and if it is permissible to set the time for only one time going to bed. He (the Imam) said, ‘Yes, it is permissible.’”