Remembrance 3 from Chapter 331
Words which it is deplorable to use
We relate in Sharḥ as-Sunnah that Imam Abū Muḥammad al-Baghawī, may Allah have mercy on him, said: “It does not matter if the one who is in charge of the affairs of the Muslims is called ‘Leader of the Believers’ or ‘Khalīfah’—even if he acts contrary to the conduct of the just leaders—because he deals with the concerns of the believers and because the believers listen to him.” He said, “He is called the Khalīfah because he succeeds those who have been before him and he takes their place.” He also said: “None should be called the Vicegerent of Allah after Adam and Dāwūd, peace be upon them both. Allah 
says: ‘I will create a vicegerent on the earth.’ [13].Allah says: ‘Dāwūd, We have made you a vicegerent in the earth.’ From Abū Mulaykah it is reported that a man said to Abū Bakr 
: “O Khalīfah of Allah.” He said: “I am the Khalīfah of Muḥammad 
and I am happy with that.” A man said to ‘Umar ibn ‘Abd al-‘Azīz “O Khalīfah of Allah.” He said: “Woe to you, this is far-fetched! My mother named me ‘Umar. If you call me by that name, I will accept it. Then I grew up and I was given the nickname Abū Ḥafṣ. If you call me by that, I will accept it. Then you put me in charge of your affairs and you named me ‘Leader of the Believers’. It is enough for you to call me by that title.”