Bukhari

Benefits and Issues:
The demand of utmost fear of Allah and deep understanding of His religion is thorough action and complete caution.
Then, who can be more cautious than the Prophet (sallallahu alayhi wa sallam)? Therefore, it is obligatory to follow him in actions.
And he alone is the example for the Ummah.
Except in those matters in which his exemption is established.

Benefits and Issues:
➊
This explicitly states that the Messenger of Allah (sallallahu alayhi wa sallam) would perform ritual bath (ghusl) after the call to prayer (adhan) of Fajr, meaning that there is no harm if some time passes in a state of major ritual impurity (janabah) while fasting.

➋
Hazrat Mutarrif rahimahullah asked his teacher the aforementioned question so that no one would be under the misconception that there is leniency in the legal ruling in the case of voluntary (nafl) fasts, and perhaps it would not be so in the case of obligatory fasts. Imam Shafi’i clarified that in this matter, there is no difference between obligatory and voluntary fasts.

➌
One should not be under the misconception that perhaps this ruling is only in the case of becoming impure (najis) due to a dream, because this condition is not within a person’s control. In Hadith: 1704, it is explicitly stated that even if the state of ritual bath (ghusl) is required due to marital relations, the legal ruling remains the same: if one performs ritual bath after the call to prayer (adhan) of Fajr, the fast is valid.

Hadith Authentication: [وأخرجه ابوداود 3389، من حديث ما لك، ومسلم 1110/79، من حديث عبد الله بن عبدالرحمن الانصاري به ● سقط من الأصل واستدركته من رواية يحي بن يحي]
Jurisprudential Points:
➊ The Noble Prophet sallallahu alayhi wa sallam was completely free from sins. No sin was ever committed by him, neither before prophethood nor after it. «صلى الله عليه و آله و سلم وفداه أبى و أمي و روحي»
➋ If, during the night, ritual impurity (janabah) becomes obligatory upon someone due to a wet dream, it is not necessary for him to perform the ritual bath (ghusl) immediately; rather, the bath is connected to the prayer. Therefore, a fasting person may first partake in the pre-dawn meal (suhoor) and then perform the ritual bath afterwards.
➌ Although the Noble Prophet sallallahu alayhi wa sallam was human, he was not like us; rather, he was sent as the best of mankind and a light of guidance. Even his perspiration was more fragrant than musk.
➍ Even though the Messenger of Allah sallallahu alayhi wa sallam was the leader of both worlds, he was not exempt from the legal rulings; so how can other people be absolved from deeds and rulings?
➎ Also see [الموطأ حديث : 436، 395، البخاري 1925، 1926، ومسلم 1931، 1932، 1109/78]

Hadith Authentication:
[وأخرجه مسلم 1109/78 و ابوداود 2388 من حديث ما لك به]

Jurisprudential Points:
➊ If a person is required to perform a ritual bath (ghusl) due to a compulsory reason, he may perform the ritual bath after eating suhoor; this will not affect the validity of his fast.
See also [الموطأ حديث: 302، و ابوداود 3389، ومسلم 1110/79]