(It is obligatory upon all the accountable persons) to embrace the religion of Islam
(It is obligatory upon all the accountable persons), i.e., those who are pubescent, sane, and have received the basic call of Islam—meaning they have received the message that no one is God except Allah and that Muhammad is the Messenger of Allah—(to embrace the religion of Islam) immediately if they were blasphemers. Likewise, it is obligatory on all the accountable persons (to remain steadfast to it), i.e., to adhere persistently to Islam in such a way that one’s heart is devoid of any intention or hesitation to leave Islam in the future, because the one who intends to or hesitates about leaving Islam in the future blasphemes immediately. (And) it is obligatory on them (to comply with what is obligatory upon them of its rules), i.e., to adhere to the rules which the Religion ordered him to follow by fulfilling all the obligations and refraining from all the sins. (This means that every accountable person must be Muslim, stay Muslim, and follow the rules of Islam.)