Xalifa hokim bo‘lib, uning vazifalari hukmronlik, ijro (amalga oshirish) va xalqning ishlariga g‘amxo‘rlik qilishdan iboratdir. Hukmronlik, ijro va g‘amxo‘rlikni amalga oshirish ma’muriy harakatlarni talab qiladi. Bu esa xalifaga bu vazifalarni bajarishda yordam beradigan, u bilan yaqindan ishlaydigan maxsus bo‘limni tashkil etishni zarur qiladi. Shuning uchun xalifa tomonidan tayinlanadigan ijro etuvchi yordamchi (mu’avin at-tanfiz) kerak bo‘ladi; u ma’muriy ishlarni boshqaradi, ammo hukmronlik ishlarini emas. U, masalan, vali yoki amil tayinlashga haqli emas, xalq ishlariga ham aralashmaydi. Uning vazifalari faqat ma’muriydir, ya’ni xalifa yoki vakolatli yordamchi tomonidan berilgan hukm buyruqlari va ma’muriy topshiriqlarni bajarishdir. Shu sababli u ijro etuvchi yordamchi deb ataladi.
Fuqaholar uni “vazir tanfiz” deb atashgan, ya’ni “Mu’awin at-tanfiz” ma’nosida, chunki “vazir” so‘zi lug‘atda “yordamchi” ma’nosida ishlatiladi. Ular aytadilar: bu vazir xalifa, raiyyat va valilar o‘rtasidagi vositachi bo‘lib, unga yuborilgan buyruqlarni yetkazadi, uning qoidalarini ijro etadi, xalifani valilarning tayinlanishi hamda chegaralarda joylashgan qo‘shin va harbiy guruhlarning tayyorlanishi haqida xabardor qiladi. Shuningdek, bu idoralardan kelgan barcha narsalarni xalifaga yetkazadi va yuzaga kelishi mumkin bo‘lgan barcha yangi masalalar haqida unga ma’lum qiladi, shunda xalifa ularga oid buyruqlarini amalga oshira oladi. Bu uni buyruqlarni ijro etishda yordamchi qiladi, ularni boshqarishda emas yoki ularni unga ishonib topshirishda emas. U hozirgi davlat rahbarining devoni boshlig‘iga o‘xshaydi. Ijro etuvchi yordamchi xuddi vakolatli yordamchi kabi to‘g‘ridan-to‘g‘ri xalifaga bog‘langani uchun u xalifaning yaqin atrofidagilar (hashami) qatoriga kiradi. Uning vazifasi halifa bilan aloqada bo'lishni va halifani kuzatib borishni, uning bilan kecha-kunduz istalgan vaqtda yakka tartibda uchrashishni talab qiladi, bu esa ilohiy qoidalarga ko'ra ayollar uchun belgilangan shartlarga zid keladi. Shu sababli ijroiy yordamchi erkak bo'lishi kerak. Bundan tashqari, ijroiy yordamchi kofir bo'la olmaydi; u musulmon bo'lishi shart, chunki u halifaning xizmatchilari tarkibiga kiradi. Buning sababi, Alloh (SWT) aytadi:
The Khalifah is a ruler, whose duties include ruling, execution, and looking after people’s affairs. The carrying out of ruling, execution and guardianship requires administrative actions. This necessitates the setting up of a special department that works closely with the Khalifah to manage tasks that help him carry out the Khilafah’s duties. Thus an executive assistant is required, to be appointed by the Khalifah to run the administrative affairs but not the affairs of ruling. He does not perform any ruling duties like the delegated assistant. He is not allowed, for example, to appoint a Wali or an amil, nor to manage people’s affairs. His duties are merely administrative, i.e. to execute the ruling orders and the administrative tasks issued by the Khalifah or the delegated assistant. This is why he is known as the executive assistant. Jurists used to call him ‘wazir tanfidh’ which simply means Mu’awin al-Tanfidh, on the basis that the word wazir is linguistically used to mean ‘the assistant’. They said that this wazir is an intermediary between the Khalifah, the subjects and the Walis, who conveys the orders issued to him, executes his rules, informs the Khalifah about the appointment of Walis, and about the preparation of task forces and armies stationed at the frontiers. He also conveys to the Khalifah whatever comes from these offices and informs him of all new matters that may arise so that he can implement the Khalifah’s orders regarding them. This makes him an assistant in executing commands, not in taking charge over them, or entrusting him with them. He is similar to the head of the divan of the head of the state at the present time. Since the executive assistant is linked directly to the Khalifah just like the delegated assistant, he is part of the Khalifah’s entourage. His task requires contact with the ruler (Khalifah) and requires pursuance with the Khalifah and meeting with him in isolation at any time, day or night, a matter that disagrees with the conditions for a woman according to the divine rules. Therefore, the executive assistant has to be a man. In addition the executive assistant cannot be a disbeliever; he must be a Muslim, for he is part of the Khalifah’s entourage. This is because Allah (S.W.T ) says:.