Waajib shi ne abin da Shari'a ta nema a aiwatar da shi ta hanyar buƙata mai ƙarfi (Talab Jaazim), kuma yana iya faruwa cewa ba za a cika Waajib ba sai an aiwatar da wani aiki wanda cikar Waajib ɗin ta dogara a kansa. Misali shi ne wanke gwiwar hannu a cikin alwala, kuma hakan saboda cikar aiwatar da Waajib ɗin, wato wanke hannaye har zuwa gwiwar hannu, ba zai cika ba sai an wanke wani ɓangare na gwiwar hannu. Hakan kuwa saboda ƙarshen abin da ake nema, wato gwiwar hannu, yana cikin abin da ake nema, wato hannu/gaɓa. Saboda haka, cika wannan Waajib na wanke hannaye/gaɓoɓi ya dogara ne da wankewar da ake yi har zuwa wani ɓangare na ƙarshen wurin, watau wanke wani ɓangare na gwiwar hannu. Sabili da haka, wanke wani ɓangare na gwiwar hannu Waajib ne, domin Waajib ɗin wanke hannaye (watau hannu) ba ya cika sai ta hanyar wannan aiki, watau wanke wani ɓangare na gwiwar hannu. Wannan yana ginuwa ne a kan ƙa'idar (Qaa'idah) da ake amfani da ita:

The Waajib is that which the Shaari’ has requested to be undertaken by way of a decisive request (Talab Jaazim) and it can be the case that the completion of the Waajib cannot be fulfilled unless another action is undertaken upon which the fulfilment of the Waajib rests. That is like washing the elbows in the act of Wudoo’ and that is because the completion of the undertaking of the Waajib, which is washing the hands until the elbows, cannot be fulfilled unless a part of the elbows are washed. That is because the end point of what is being sought, which is the elbows, is included with the sought after matter, which is the hands/forearms. Therefore, the fulfilment of this Waajib to wash the hands/forearms rests upon the washing taking place upon a part of the endpoint i.e. washing a part of the elbows. Consequently, washing part of the elbows is Waajib because the Waajib of washing the hands (i.e. arms) is not completed except through this action i.e. washing a part of the elbows. This is built upon the Qaa’idah (principle):

Mithlu dhaalika kafuwar Khalifah ko lissafta mai mulki (muhasabat al-haakim) saboda dukkansu wajibi ne kamar yadda Shari'i ya bayyana su a cikin Ayoyi da Hadisai, kuma wajibi ba ya cika sai da kafa tsarin siyasa mai aiki don kafa Khalifah da lissafta mai mulki. Hakan ne saboda mutum ɗaya ba zai iya aiwatar da wannan aiki ba saboda rashin ikonsa na cika abin da aikin ya bukata shi kaɗai. Saboda haka kafa wata ƙungiya ta siyasa mai tsari wajibi ne a kan Musulmi, domin: "Abin da wajibi ba ya cika sai da shi, to shi ma wajibi ne." Don haka, idan Musulmi ba su kafa wata Takattul (ƙungiya mai tsari) ba, to za su yi zunubi, domin ba su aiwatar da abin da ya zama dole a gare su su aiwatar don cika wajibin.

Similar to that is the establishment of the Khalifah or accounting the ruler because these are both Waajib as stated by the Shaari’ in the Aayaat and Ahaadeeth and the Waajib is not completed except by the establishment of a political structure that works to establish the Khalifah and account the ruler. That is because the individual cannot undertake that action because of his incapability to fulfil the undertaking of this action (and what it demands) by himself. As such establishing a political structured bloc is an obligation upon the Muslims because: “That which the Waajib is not completed except with it, is Waajib”. Consequently, if the Muslims did not establish a Takattul (structured grouping) they would be sinful because they would not have undertaken that which is necessary for them to undertake and fulfil the Waajib.

Haka kuma, dukkan abin da wajibi ba zai cika ba sai da shi, to shi ma wajibi ne. Wannan idan aikata wannan abin yana cikin iyawar mukallafi ne; idan kuma ba ya cikin iyawarsa, to ba wajibi ba ne. Wannan saboda fadin Allah Ta'ala:

Similarly, in this way, every matter that the Waajib cannot be fulfilled except with it, is Waajib. That is if the undertaking of this matter is within the capability of the Mukallaf and if it is not within his capability then it is not Waajib. That is due to the Qawl of Allah Ta’Aalaa: