قال الله عز وجل...

Another obligatory fasting is for two consecutive months as a compensation for divorcing one’s wife by Zihar** [959] ** in case one cannot find a slave to free as the Blessed the Sublime God says, ‘But those who divorce their wives by Zihar, then wish to go back on the words they uttered, (it is ordained that such a one) should free a slave before they touch each other: Thus are ye admonished to perform: and God is well-acquainted with (all) that ye do.

And if any has not (the wherewithal), he should fast for two months consecutively before they touch each other.’ [960] Three days of fasting is obligatory for the compensation for a deliberate oath for the person who cannot feed the poor people as the Blessed the Sublime God says, ‘Allah will not call you to account for what is futile in your oaths, but He will call you to account for your deliberate oaths: for expiation, feed ten indigent persons, on a scale of the average for the food of your families; or clothe them; or give a slave his freedom.

If that is beyond your means, fast for three days. That is the expiation for the oaths ye have sworn. But keep to your oaths. Thus doth Allah make clear to you His signs, that ye may be grateful.’ [961] This fasting should be performed continuously and it cannot be done on various scattered days.

Then there is the fasting for shaving the hair on the head before the offering reaches the place of sacrifice as the Blessed the Sublime God has ordained, ‘And complete the Hajj or Umra in the service of Allah. But if ye are prevented (from completing it), send an offering for sacrifice, such as ye may find, and do not shave your heads until the offering reaches the place of sacrifice.

And if any of you is ill, or has an ailment in his scalp, (necessitating shaving), (He should) in compensation either fast, or feed the poor, or offer sacrifice…’ [962] One is free to perform either of the above three, but if he decides to fast he should fast for three days.