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):

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.

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: