Accordingly, if he thereafter intends to observe a voluntary fast during the course of the day, that is permissible—unless it is Ramadan. If it is Ramadan, then it is not permissible, because no fast other than that of Ramadan is valid during Ramadan.

Issues:

First: A person is observing a voluntary fast, then intends to break it. He is then told, “How can you break your fast when less than half the day remains?” So he says, “Then I am fasting.” Will he be credited with the fast of a full day, or only from the second intention?

Answer: From the second intention, because he discontinued the first intention and became one who was not fasting.

Second: A person is fasting and resolves that, if he finds water, he will drink it. Does this invalidate his fast?

Answer: It does not invalidate his fast, because intending a prohibited act during an act of worship does not invalidate that worship; rather, it is invalidated only by actually doing it, not by merely intending to do it.

This is a useful principle: whoever intends to withdraw from an act of worship invalidates it, except in Hajj and Umrah; whereas whoever intends to commit something prohibited during an act of worship does not invalidate it unless he actually commits it.

There are examples of this, including what we have mentioned here regarding fasting.

Another example is a person who is awaiting a call from someone by telephone. He begins the prayer intending that, if the person whose call he is awaiting speaks to him, he will answer him. If that person does not call him, his prayer is not invalidated.

Third: It has previously been stated that whoever intends to break his fast has broken it. Is he then permitted to continue breaking his fast by eating and drinking, for example, while it is Ramadan?