Suhur is recommended
Allah allowed eating and drinking until dawn, it represents proof that Suhur is encouraged, since it is a Rukhsah (concession or allowance) and Allah likes that the Rukhsah is accepted and implemented. The authentic Sunnah indicates that eating the Suhur is encouraged. It is reported in the Two Sahihs that Anas narrated that Allah's Messenger said:
«تَسَحَّرُوا فَإِنَّ فِي السَّحُورِ بَرَكَة»
(Eat the Suhur, for there is a blessing in Suhur.)
Muslim reported that `Amr bin Al-`As narrated that Allah's Messenger said:
«إِنَّ فَصْلَ مَا بَيْنَ صِيَامِنَا وصِيَامِ أَهْلِ الْكِتَابِ أَكْلَةُ السَّحَر»
(The distinction between our fast and the fast of the People of the Book is the meal of Suhur.)
Imam Ahmad reported that Abu Sa`id narrated that Allah's Messenger said:
«السَّحُورُ أَكْلُهُ بَرَكَةٌ فَلَا تَدَعُوهُ، وَلَوْ أَنَّ أَحَدَكُمْ تَجْرَعُ جُرْعَةَ مَاءٍ، فَإِنَّ اللهَ وَمَلَائِكَتَهُ يُصَلُّون عَلَى الْمُتَسَحِّرِين»
(Suhur is a blessed meal. Hence, do not abandon it, even if one just takes a sip of water. Indeed, Allah and His angels send Salah (blessings) upon those who eat Suhur.)
There are several other Hadiths that encourage taking the Suhur, even if it only consists of a sip of water.
It is preferred that Suhur be delayed until the time of dawn. It is recorded in the Two Sahihs that Anas bin Malik narrated that Zayd bin Thabit said, "We had Suhur with Allah's Messenger and then went on to pray.'' Anas asked, "How much time was there between the Adhan (call to prayer) and the Suhur'' He said, "The time that fifty Ayat take (to recite).''
Imam Ahmad recorded Abu Dharr saying that Allah's Messenger said:
«لَا تَزَالُ أُمَّتِي بِخَيْرٍ مَا عَجَّلُوا الْإِفْطَارَ وَأَخَّرُوا السُّحُور»
(My Ummah will always retain goodness as long as they hasten in breaking the fast and delay the Suhur.)
There are several Hadiths that narrate that the Prophet called Suhur "the blessed meal.''
There are narrations from several of the Salaf that they allowed the Suhur to be eaten later until close to Fajr. This is is reported from Abu Bakr, `Umar, `Ali, Ibn Mas`ud, Hudhayfah, Abu Hurayrah, Ibn `Umar, Ibn `Abbas and Zayd bin Thabit. It is also reported from many of the Tabi`in, such as Muhammad bin `Ali bin Husayn, Abu Mijlaz, Ibrahim An-Nakha`i, Abu Ad-Duha, Abu Wa'il and other companions of Ibn Mas`ud. This is also the opinion of `Ata', Al-Hasan, Hakam bin `Uyainah, Mujahid, `Urwah bin Az-Zubayr, Abu Sha`tha' Jabir bin Zayd, Al- A`mash and Ma`mar bin Rashid. We have mentioned the chains of narrations for their statements in our (Ibn Kathir's) book about Siyam (Fasting), and all praise is due to Allah.
It is also recorded in the Two Sahihs that Al-Qasim said that `A'ishah narrated that Allah's Messenger said:
«لَا يَمْنَعُكُمْ أَذَانُ بِلَالٍ عَنْ سَحُورِكُمْ، فَإِنَّهُ يُنَادِي بِلَيْلٍ، فَكُلُوا وَاشْرَبُوا حَتَّى تَسْمَعُوا أَذَانَ ابْنِ أُمِّ مَكْتُومٍ، فَإِنَّهُ لاَ يُؤَذِّنُ حَتَّى يَطْلُعَ الْفَجْر»
(The Adhan pronounced by Bilal should not stop you from taking Suhur, for he pronounces the Adhan at night. Hence, eat and drink until you hear the Adhan by Ibn Umm Maktum, for he does not call the Adhan until dawn.)
This is the wording collected by Al-Bukhari.
Imam Ahmad reported that Qays bin Talq quoted from his father that Allah's Messenger said:
«لَيْسَ الْفَجْرُ الْمُسْتَطِيلَ فِي الْأُفُقِ وَلَكِنِ الْمُعْتَرِضُ الْأَحْمَر»
(Dawn is not the (ascending) glow of white light of the horizon. Rather, it is the red (radiating) light.)
Abu Dawud and At-Tirmidhi also recorded this Hadith, but their wording is:
«كُلُوا واشْرَبُوا، وَلَا يَهِيدَنَّكُمُ السَّاطِعُ الْمُصْعِدُ، فَكُلُوا واشْرَبُوا حَتَّى يَعْتَرِضَ لَكُمُ الْأَحْمَر»
(Eat and drink and do not be rushed by the ascending (white) light. Eat and drink until the redness (of the dawn) appears.)
Ibn Jarir (At-Tabari) recorded that Samurah bin Jundub narrated that Allah's Messenger said:
«لَا يَغُرَّنَّكُمْ أَذَانُ بِلَالٍ وَلَا هَذَا الْبَيَاضُ لِعَمُودِ الصُّبْحِ حَتَّى يَسْتَطِير»
(Do not be stopped by Bilal's Adhan or the (ascending) whiteness, until it spreads.) Muslim also recorded this Hadith.