Answered by Shaykh Abul ‘Ataa Ahmad Banaja (may Allah preserve him)
What is the ruling on breaking fast when invited for any feast? For example, for breakfast, lunch or dinner when the brothers meet.
The answer for your question is, you are allowed to break the fast before the time of opening fast (iftaar) reach. For sake of any reason, even without a reason, if it is a voluntary fast. Not like the fasting in Ramadan or fasting for Nadr or Kaffaarah. If it’s not among these three, you have the choice to break it, because the evidence says that. We have Hadith ‘Aisha, Hadith Ibn ‘Abbas, Hadith Abi Hurairah (رضي الله عنهم) and other Hadiths that shows, Prophet ﷺ opened his voluntary fast, in the mid-day, without a reason.
So, here is the rule. This understanding is not applied to all kinds of worship. The rule says, if you start the worship correctly, you must complete it, unless you have a reasonable cause to break it in the middle, except if Daleel shows that you have choice (to break it), like in the case of voluntary fasting. The evidence for this is Allaah’s saying:
“وَلَا تُبۡطِلُوۤا۟ أَعۡمَـٰلَكُمۡ”
“And do not invalidate your deeds.” [Surah Muhammad 33]
So, this is applied to Salaah, Hajj and all kinds of worship. When you start, complete it till the end, unless you have a valid reason to cut it in the middle.
Example, if you are praying, and suddenly your house got burned, and it will harm you, you can cut off your prayer for these kinds of reasons. Otherwise you are not allowed.
But if you are fasting voluntarily, you can break it even without a reason, because you have a choice (from the evidence).
بارك الله فيك