Simplify the following text for a Grade 7 native English-speaking person.
Original: In the Will and Testament ` Abdu ` l-Bah Ã 's half-brother , Muhammad ` AlÃ , was mentioned by name as being subordinate to ` Abdu ` l-Bah Ã .
Simplified: ` Abdu ` l-Bah Ã spent most of his adult life in prison or under arrest , because of his father 's new religion .