能够作为实现某项瓦吉卜（wājib）之前提的事物，可分为两类：一，该义务以它为条件；二，该义务并不以它为条件。若义务以它为条件，则完成此条件不构成瓦吉卜。真正的瓦吉卜，是由证据所确立其义务的那一项。例如某一特定的礼拜（salāt），其义务以获得洁净为条件，然而从确立礼拜义务的经文来看，洁净本身并不是一项义务，它只是履行该义务的条件；礼拜的义务，是在条件具备时的礼拜。 至于作为实现瓦吉卜之前提、但并非法律条件，而只是现实层面的条件的事物，又分为两类：一，在mukallaf（负有责任者）能力范围之内的；二，不在其能力范围之内的。前者本身就因确立原初瓦吉卜的同一条经文而成为瓦吉卜，其义务与立法者经文所规定之事项的义务完全相同。例如洗涤手肘（mirfaqayn），若不洗涤，则无法完成洗至手肘的瓦吉卜；而完成它依赖于洗涤手肘的至少一部分，因此洗涤手肘的一部分便是瓦吉卜，尽管经文并未明文提及。这是因为经文提到了某事，而该事的完成依赖于此，所以该经文既包含原初的瓦吉卜，也包含其所依赖之事。经文对这一后续义务的指示，是一种隐含的指示（dalālat al-iltizām）。另一个例子是：当哈里发制度不存在时，为建立哈里发而设立政治架构，或为了问责统治者而设立相应机制。 确立哈里发国是一项义务，监督统治者也是一项义务。仅凭个人无法妥善履行这些义务，因此需要组织穆斯林群体，使他们能够集体履行这些义务。因此，穆斯林有义务建立一个能够确立哈里发国或监督统治者的团体。若他们不这样做，则全体都有罪，因为他们没有完成履行一项义务所必需的事情。如果他们建立了一个团体，但该团体无法完成所需的任务，那么他们依然有罪，也没有履行义务。这是因为义务不仅仅是建立一个团体，而是建立一个能够履行所需义务的团体。

A thing required to fulfill a wājib can be of two types: i) it can be such that the obligation is conditional upon it, or ii) it can such that the obligation is not conditional upon it. If the obligation is conditional upon it than there is no difference in that fulfilling that condition is not a wājib. Rather the wājib is that whose obligation is established by the evidence. An example of this is the obligation of a specific salāt, which is conditional upon the attainment of purity. Yet the purity is not an obligation from the perspective of the address which establishes the obligation of the salāt. Rather it is a condition for the performance of that obligation, and that obligation in the address of salāt is but that salāt if the condition exists. As for the thing required to fulfill a wājib but not as a (legal) condition, rather as a condition of reality, then this is of two types: i) that which is within the ability of the mukallaf and ii) that which is not within the ability of the mukallaf. As for the former, than it is wājib by the same address which establishes the original required wājib, and its obligation is entirely like the obligation of the matter brought by the address of the Legislator. An example of this is washing the elbows [mirfaqayn], without which the wājib of washing the arms up to the elbows cannot be accomplished. Accomplishing it depends on washing at least a part of the elbows; hence washing a part of the elbows is wājib, even though the address did not expressly state this. This is because the address came with that whose accomplishment depends on this, hence that address includes the original wājib as well as that which its performance depends upon. The indication of the address upon this later obligation is an implicative indication [dalālat al-iltizām]. Another example is the establishing of a political structure in order to establish the Khalīfah when one does not exist, or to account the rulers. Establishing the Khalīfah is an obligation, as is accounting the rulers. Fulfilling these obligations properly is not possible by individuals alone, and hence requires the structuring of a group of the Muslims who as a collective are able to fulfill them. Thus it becomes wājib upon the Muslims to establish a group able to establish the Khalīfah or account the rulers. If they do not do this they are all sinful, because they did not fulfill that which was required for the fulfillment of a wājib. And if they establish a group but one unable to fulfill the required tasks they are still sinful and have not fulfilled the obligation. This is because the obligation is not to merely establish a group, but to establish a group able to fulfill the required obligation.

至于那些超出受命者能力范围的事情，则不是必须履行的（瓦吉卜），因为真主说：

As for that which is not within the ability of the mukallaf, then it is not wājib, because of the saying of Allah,

“安拉不会让任何灵魂承担其力所不能及的责任……”（《黄牛》：286）；先知（愿主福安之）说：“……如果我命令你们做某件事，你们就尽力去做。”（布哈里、穆斯林辑录）。另外，要求人承担其能力之外的责任是不被允许的，因为这必然导致将不义归于安拉，而这是不被允许的。

“Allah does not burden a soul with more than it can bear…” (al-Baqarah: 286); and his (saw) saying, “…and if I command you to do a thing than do of it as much as you are able” (Bukhari, Muslim), and because it is not permissible to make one responsible for that which is beyond their ability, as this necessitates the attribution of oppression to Allah, and this is not permissible.

总而言之,完成一项wājib(义务)所必需之物,本身也是wājib,无论这一要求是通过确立原初wājib的同一依据,还是通过另一依据而成立。这不论该事物是否为sabab(法因)——即其存在必然导致hukm(判定)存在、其不存在必然导致hukm不存在的事物;还是shart(法定条件)——即其不存在必然导致hukm不存在、但其存在既不必然导致hukm存在,也不必然导致hukm不存在的事物。也不论该sabab是shar'ī(律法性的),如履行义务释放奴隶时所需的应有年龄;是理性的,如导致必须认知之事的理性判断;还是‘ādī(习惯性的),如义务宰杀中割断颈部的动作。同样,也不论shart是律法性的,如wudū(小净);是理性的,即命令所必然要求之物,如避免与所命令之事相反的行为;还是习惯性的,即按通常情况所必需之物,如在wudū中洗涤头部的一部分。 因此,一事物的义务使其所无法缺少的事物也成为义务,也就是说,履行某事的法律责任必然导致履行其所不可缺少之事的法律责任。由此得出原则:“完成一项wājib所必需之物,本身也是wājib。”

In sum, the thing required to fulfill a wājib is itself wājib, either by the same address which establishes the original wājib or by another address. This is irrespective of whether this thing is a sabab [legal cause] – that whose presence necessitates the presence (of the hukm) and whose absence necessitates its absence – or a shart [legal condition] – that whose absence necessitates the absence (of the hukm) but whose presence necessitates neither its presence nor absence. It is also irrespective of whether the sabab is legal [shar’i] like the required tense in relation to the obligatory emancipation (of a slave), rational, like the (intellectual) assessment which leads to obligatory knowledge, or normal [‘ādī] like the incision of the neck in the obligatory slaughtering. Similarly it is irrespective of where the shart is legal, like the wudū, rational - that which is a rational necessity for what is commanded - like leaving the opposite of what is commanded, or normal – that which is required as a matter of usual occurrence – like washing a part of the head in wudū. Hence the obligation of a thing obligates that which it cannot be fulfilled without, that is, legal responsibility to fulfill a thing necessitates the legal responsibility of that which it cannot be fulfilled without. And thus we arrive at the principle, “that which is required to fulfill a wājib is itself wājib.”