someone eating and drinking and says to him, “What are you doing? You are fasting!” The man replies, “The sun has set.” He answers, “It has not set yet.” At that point the eater must stop immediately, for his excuse has fallen away.

If someone asks, “When I see a fasting person eating, and I know he has forgotten, am I obliged to remind him?”—the answer is yes, you must remind him. Your brother has an excuse because he forgot, but once you are aware of it you are required to alert him. For that reason the Prophet ﷺ said regarding the prayer, “If I forget, remind me.” He commanded the Companions to remind him when he forgot; the same principle applies when you see a fasting person eating or drinking out of forgetfulness—remind him, just as you would correct someone you saw praying while facing the wrong direction.

The point is this: whenever your brother falls into something that is not lawful for him, you have to bring it to his attention, because forgetfulness and error are common.

The author then cites the ḥadīth of Laqīt ibn Ṣabrah (may Allah be pleased with him), in which the Prophet ﷺ said: “Perform your ablution thoroughly, run your fingers between the digits, and sniff water into the nose deeply—unless you are fasting.”

“Perform your ablution thoroughly” means carry it out in a complete and perfect manner. The Arabic term ispāgh conveys the sense of perfecting something, as in the Almighty’s words: “He has perfected for you His favors, both visible and hidden.” The second instruction is “run your fingers between the digits,” especially the toes, making sure that water passes between them, for the toes are close together and water may not otherwise reach between them. Finally, “sniff water into the nose deeply…”