The ruling on a voluntary fast if a reason to break it arises

Question:
If a person is fasting voluntarily, for what reasons may he break his fast?

Answer:
There is no harm. The one who fasts voluntarily is the master of his own affairs; if he breaks his fast, there is no harm. If a need arises, he breaks his fast, such as if a guest is with him or if he has a need, he breaks his fast.
Q: Or to strengthen himself for some of the works of this world?
The Shaykh: There is no harm, there is no blame on him.