Imam Al-Nawawi's Riyad-us-Saliheen
Chapter 221
Merit of Suhur (Predawn meal in Ramadan) and the Excellence of Delaying having it till before Dawn

1229. Anas (May Allah be pleased with him) reported: The Messenger of Allah (sallallaahu ’alayhi wa sallam) said, "Eat Suhur (predawn meal). Surely, there is a blessing in Suhur.''
[Al-Bukhari and Muslim].

Commentary: This Hadith tells us that Suhur is Masnun (Sunnah of the Prophet (sallallaahu ’alayhi wa sallam)), even if one takes a small quantity of food. This meal is blessed and maintains one's energy and vitality during Saum. Against this, if a person goes to sleep after taking his dinner to save himself from the inconvenience of getting up before dawn or takes Suhur early will be, on one side, disobeying Messenger of Allah (sallallaahu ’alayhi wa sallam) , while on the other side, he will be feeling hunger and thirst very early and very much as he himself has increased the period of fasting by not taking the Suhur. Subhan Allah! How the weaknesses of man have been taken into account in the teachings of Islam while suitable provision has been provided to overcome them!

1230. Zaid bin Thabit (May Allah be pleased with him) reported: We took Suhur (predawn meal) with the Messenger of Allah (sallallaahu ’alayhi wa sallam) and then we stood up for (Fajr) Salat (prayer). It was asked: "How long was the gap between the two?'' He replied: "The time required for the recitation of fifty Ayat.''
[Al-Bukhari and Muslim].

Commentary:  We learn from this Hadith that Suhur should be taken towards the end of its timing. This is the Sunnah of the Prophet (sallallaahu ’alayhi wa sallam). One should, however, take care that it is done before dawn.

1231. Ibn `Umar (May Allah be pleased with them) reported: The Messenger of Allah (sallallaahu ’alayhi wa sallam) had two Mu'adhdhin: Bilal and Ibn Umm Maktum (May Allah be pleased with them). The Messenger of Allah (sallallaahu ’alayhi wa sallam) said, "Bilal proclaims Adhan [call to Salat (prayer)] at fag end of night, so eat and drink till Ibn Umm Maktum pronounces Adhan.'' Ibn `Umar (May Allah be pleased with them) added: And the gap between their Adhan was not more than the time spent in one's getting down and the other's climbing (the minaret).
[Al-Bukhari and Muslim].

Commentary:  We learn from this Hadith that in the days of the Prophet (sallallaahu ’alayhi wa sallam) there used to be two Mu'adhdhin  and two Adhan  in the morning. The first Adhan was meant to warn the people who were taking the Suhur meals that the time for the Suhur was about to finish and they should make preparation for Fajr prayer. Soon after that there was a second Adhan by another Mu'adhdhin which signified that the time for food was finished and people should attend to Salat. This practice was, however, terminated later so much so that we do not find it even in the times of the Companions of the Prophet (sallallaahu ’alayhi wa sallam) and that of At-Tabi`un (the successors of the Prophet's Companions) and Tabi`ut-Tabi`in (the followers of the Successors). In any case, this practice can be revived.

So far, the question of time between the two Adhan is concerned, `Ulama' have stated that after announcing the Adhan, Bilal used to be engaged in prayer, etc., and waited for the daybreak. When the time for the daybreak drew near, he would then come down and inform Ibn Umm Maktum who would then make Wudu', and then proceed to call the Adhan at the beginning of the daybreak. (Ibn Allan).

1232.  `Amr bin Al-`As (May Allah be pleased with him) reported: The Messenger of Allah (sallallaahu ’alayhi wa sallam) said, "The difference between our observance of Saum (fasting) and that of the people of the Scriptures is Suhur (predawn meal in Ramadan).''
[Muslim].

Commentary:  We learn from this Hadith that Suhur is a distinctive mark with which Allah has blessed the Muslim Ummah.