I fast the three 'white days' i.e., the 13th, 14th and 15th of every lunar month. What is the ruling for fasting on the 13th of Dhul-Hijjah since it is among the days of Tashreeq? Please note that I will not perform hajj this year.

The Prophet (peace and blessings be upon him) recommended that we fast the three 'white days' of every [lunar month], the day of 'Arafa, 'Ashura (10th of Muharram) and either the day preceding or following it, and six days from the month of Shawwal. The person who fasts on [any of these] days is promised a great reward. However, there are certain days on which it is impermissible to fast. These are:
- 'Eid al-Fitr.
- 'Eid al-Adha.
- Ayam al-Tashreeq [the three days following 'Eid al-Adha].

The Prophet (peace and blessings be upon him) called these days the days of food and drink.

If a person wants to fast the three 'white days' of the month of Dhul-Hijjah, it is unlawful for him to fast the 13th since the Prophet forbade anyone from fasting on this day. The fast of anyone who does so is invalid.