What is the ruling if the master says, 'If you wish,' concerning freedom after death, regarding the immediacy of the wish?

Primary text

Regarding the statement 'If you wish, you are free after my death,' Al-Qadi holds that the choice (Mashia'a) must be exercised immediately, within the session (Majlis) where the statement was made. If the slave exercises it in that session, he becomes a Muddabbar. If the choice is delayed beyond the session, the condition lapses, and he does not become a Muddabbar through a later choice. This is based on the ruling concerning the statement, 'Choose yourself' (Ikhtari nafsak), where the choice is confined to the session.