Actually, it is obligatory to advise the person eating or drinking forgetfully in the daytime of Ramadan. Deliberately eating or drinking during the daytime of Ramadan without any legitimate excuse is a sin. One cannot know if the person eating or drinking is doing so forgetfully or deliberately, so one is to enjoin good and forbid evil by advising the person. Moreover, to follow the saying of not notifying such unmindful persons opens a door to evil when those who break fast without any legitimate reason dare to do so in public during the daytime of Ramadan.
Dr. Husam al-Din Ibn Musa `Afana, professor of principles of Islamic jurisprudence atAl-Quds University, Palestine, states the following: Many misunderstand the Prophetic hadith narrated by Abu Hurairah (may Allah be pleased with him) in which the Prophet (peace and blessings be upon him) said, “If somebody eats or drinks forgetfully then he should complete his fast, for what he has eaten or drunk has given to him by Allah” (Al-Bukhari and Muslim).
This hadith clearly shows that anybody who forgetfully eats or drinks during the daytime of Ramadan is to complete his fast and not to break it, nor does he have to fast another day for this day because his eating or drinking is sustenance from Allah. Actually, to unmindfully drink or eat during fasting does not affect it, because such a person is excused in Islam. This is further evidenced by the following hadith: “My Ummah will be excused for what they commit by mistake, forgetfulness, or what they were forced to do” (At-Tabarani, Ad-Darqutni and Al-Hakim in different wording.)
Actually people’s claim that they do not notify such persons because what they have eaten
or drunk is sustenance from Allah is wrong because of the following:
First: Eating and drinking during the daytime of Ramadan is forbidden and an evil act that a person who sees is to forbid, even if the forgetful person is excused by Allah. Advising such persons comes under enjoining good and forbidding evil.
Second: To leave the forgetful person to continue his eating or drinking in public without advising him opens a door to evil where people will dare to break the fast during daytime in public.
Third: Advising this person is obligatory because it comes under helping one another unto righteousness and pious duty. Almighty Allah says: (Help you one another unto righteousness and pious duty. Help not one another unto sin and transgression) (Al-Ma’idah 5:2).
Fourth: This matter can be analogous to notifying the forgetful person in Prayer.
Saying “subhan Allah“ is legislated to notify the imam who forgets something in Prayer. `Abdullah ibn Mas`ud related the following hadith:
The Prophet (peace and blessings be upon him) prayed, and when he had finished the Prayer, he was asked, “O Messenger of Allah! Has there been any change in the Prayers?” He said, “What is that?” The people said, “You have prayed so much and so much.” So the Prophet bent his legs, faced the qiblah and performed two prostrations , then he finished his Prayer by salutations. When he turned his face to us he said, “If there had been any change in the Prayer, surely I would have informed you, but I am a human being like you and liable to forget as you, so if I forget, remind me, and if anyone of you is doubtful about his Prayer, he should follow what he thinks to be correct and complete his Prayer accordingly, and finish it and perform two prostrations.” (Al-Bukhari and Muslim)
Among the odd things narrated in this respect is what Al-Hafizh ibn Hajar Al-`Asqalani narrated from `Abd Ar-Raziq from `Amr ibn Juraij from `Amr ibn Dinar:
A man came to Abu Hurairah and said that he intended to fast but then he forgot and ate. Abu Hurairah said, “It is okay.” The man said, “Then I visited a man where I forgot and again ate and drank.” Abu Hurairah said, “It is Allah who fed you and gave you drink.” The man said, “Then I visited another where again I forgot and drank.” Abu Huarirah then said, “You are a person who is not accustomed to fasting.” (Fath Al-Bari 4/201)
To conclude, it is obligatory to remind the forgetful person during the daytime of Ramadan. It is not proper to leave him eating under the pretext that what he has eaten or drunk is sustenance from Allah.