The Prophet (sal Allahu alaihi wa sallam) said, “Eat suhoor for in suhoor there is blessing.” and “Verily that which separates (i.e. distinguishes) between our fast and the fasting of the People of the Book (i.e. Jews and Christians) is the eating before dawn (Suhoor).”
[Sahih al-Bukhari and Muslim]
As-Suhoor (Pre-Dawn Meal): This is eating and drinking during the last part of the night before dawn with the intention of fasting. Allah says (interpretation of the meaning):
“And eat and drink until the white thread (light) of dawn appears to you distinct from the black thread (darkness of night), then complete your Sawm (fast) till the nightfall” (Al-Baqarah 2: 187)
In these ahadith we are encouraged by the Prophet (sal Allahu alaihi wa sallam) to eat suhoor, because this helps the fasting person to fast.
We are also encouraged to delay the suhoor until the very last part of the night which is also a sign of goodness as the Prophet (sal Allahu alaihi wa sallam) said: “My Ummah (nation of followers) will not cease being upon goodness as long as they hasten in breaking the fast and delay the Sahur (pre-dawn meal).” (Musnad Imam Ahmad and it is authentic).
Also in another narration, from Zayd ibn Thaabit (radi Allahu anhu) who said: “We ate suhoor with the Messenger of Allah (sal Allahu alaihi wa sallam), then he got up to pray.” I said: “How much time was there between the adhaan and suhoor?” He said: “The time it takes to recite fifty verses.” [Sahih al-Bukhari]
What is meant by the blessing of suhoor is spiritual blessing and physical blessing. The spiritual blessing includes following the command and example of the Messenger (sal Allahu alaihi wa sallam). The physical blessing includes nourishing the body and strengthening it for the fast.
And Allah knows best!