If one begins a voluntary fast, is it permissible for him to break it without an excuse?

Question : If one begins a voluntary fast, is it permissible for him to break it without an excuse, or is it not permissible except for an excuse? This command came before the obligation of Hajj was revealed, for it was during the expedition of al-Hudaybiyyah in the sixth year of the Hijrah, and the obligation of Hajj was only in the ninth or tenth year.

Answer : Some scholars have said that in any act of worship, even if it is voluntary, once one has begun it, it is not permissible for him to exit from it except for an excuse. The correct view is that it is permissible to exit from a voluntary fast without an excuse, but it is disliked except for a valid purpose. We say it is disliked because Allah the Exalted said: And because it involves turning away from completing the act of worship and fleeing from its completion, so a person should not exit, even from a voluntary act, except for a legal reason or a valid purpose. As for the hadith of 'Aishah, perhaps the Prophet (peace and blessings be upon him) was desirous of food and wanted to give his body its due, and for this reason he said, "Indeed, I was fasting in the morning," meaning fasting a religious fast. But let us look at whether the analogy with Hajj and 'Umrah is correct. If we say it is correct and say that one who begins a voluntary act must complete it, and answer regarding the hadith that the meaning of his statement "I was fasting in the morning" is a linguistic fast, where a linguistic fast means abstention in general, whether it is an act of worship or not, the answer is that we do not accept that. As for Hajj and 'Umrah, they are specifically required to be completed in the voluntary state because they resemble jihad in the path of Allah, and jihad in the path of Allah, once begun, does not permit deviation from it; completion is required, and this is indicated by the fact
that Allah the Exalted mentioned this verse after His saying: This is an indication that Hajj and 'Umrah are part of jihad in the path of Allah. This is supported and strengthened by the hadith of 'Aishah (may Allah be pleased with her), who said: "O Messenger of Allah, And on this basis, the analogy of the remaining acts of worship with Hajj and 'Umrah is not valid.
As for the hadith, we say that interpreting it according to the linguistic meaning is contrary to the original principle and contrary to the rule agreed upon by the scholars of usul al-fiqh, which is that the literal meaning is to be taken as what the speaker intends. Therefore, what comes in the language of the Lawgiver in terms of words must be taken as the legal literal meaning, and this is necessary. This is the original principle. Accordingly, the meaning of the statement of the Prophet (peace and blessings be upon him), "I was fasting in the morning," is that he was fasting a religious fast. Yes.