19. My father said: Sa`d ibn `Abd Allah said, on the authority of Ahmad ibn Muhammad ibn `Isa, on the authority of al-Husayn ibn Sa`id, on the authority of Muhammad ibn Abu `Umayr, on the authority of Hisham ibn Salim that Abu `Abd Allah al-Sadiq :

Allah does not oblige His Servants to complete an action, nor does He forbid them form anything, without giving them the ability to do so. Then, and only then, He commands them to complete certain actions or to refrain from certain actins. Therefore, a servant (of Allah) cannot obey or disobey unless he has been given the ability to do so. The ability to act or to desist from action precedes the command, the action, apprehension, and delight.