What are the categories of fasting?

The questioner : What are the categories of fasting?

The Shaykh : Fasting is divided into two categories: the obligatory and the non-obligatory. The obligatory is the fast of Ramadan. The concept is that it may be for a specific reason, such as expiation fasts and vow fasts, or it may be without a specific reason, such as the fast of Ramadan, which is obligatory by the original law of the Shari'ah, meaning without a reason from the person obligated. As for the non-obligatory, it may be specific or general. An example of a specific fast is fasting on Mondays and Thursdays, and an example of a general fast is fasting on any day of the year. However, there is a prohibition against singling out Friday for fasting, so one does not fast on Friday unless a day before it or a day after it is also fasted. It is also established that there is a prohibition against fasting on the two days of 'Id, 'Id al-Fitr and 'Id al-Adha, and likewise against fasting on the days of Tashreeq, except for one who did not find the sacrificial animal among those who combined or performed Tamattu', in which case he fasts on the days of Tashreeq for the three days in Hajj.