` Abdu ` l-Bah Ã spent most of his adult life in prison or under arrest , because of his father 's new religion . BahÃ ` u 'll Ã h called him the `` Expounder '' of his word , meaning that only ` Abdu ` l-Bah Ã had the right to say what BahÃ ` u 'll Ã h 's writings mean . BahÃ ` u 'll Ã h was eventually released from prison but ordered into exile , and ` Abdu ` l-Bah Ã then eight joined his father on the journey to Baghdad in the winter ( January to April ) of 1853 .