An example is the address of the Almighty to Virgin Mary...

An example is the address of the Almighty to Virgin Mary (as) in which He commanded her, when confronted by others who resented the birth of Christ (as), to say: "I have surely vowed [to observe] a fast to the Beneficent God, so I shall not speak to anyone today" (Holy Qur'an, 19:26).

Muslims have learned from their Lord, the Praised and the Exalted One, that fast is one of the atonements for: 1) shaving the head during the pilgrimage (while one is still wearing the ihram ) due to a valid excuse such as sickness or a head injury, 2) the inability to offer sacrifice (I.e., hadi ), 3) killing an ally by mistake, 4) violating an oath, 5) hunting while still wearing the ihram , 6) in the case of zihar .[^1] [^1]: "Your back," an Arab during Jahiliyya may say to his wife, "looks to me like the back of my mother!" Striking such a similitude is called zihar.