1- Obligatory fasting:

-a- Intrinsic obligation: The fasting of Ramadan and making up for it.

-b- Incidental obligation'.

This is vowed fasting (nathr), the fasting of atonement, and the fasting which substitutes for slaughtering in hajj.

2- Recommended fasting: Some of which has a specific evidence, such as the first nine days of Thul Hijja, and some of which has been equested by many evidences that encourage fasting in general.

3- Makrooh fasting.

4- Forbidden fasting. (pa:289 )