Abu Dawud

534. Commentary:
➊ There are two types of dawn: the first is called "false dawn" (fajr kadhb) and the second is called "true dawn" (fajr sadiq). In Sahih Ibn Khuzaymah and Al-Mustadrak of Al-Hakim, it is narrated from Ibn Abbas radi Allahu anhuma and Jabir bin Abdullah radi Allahu anhuma that the Messenger of Allah sallallahu alayhi wa sallam said: There are two types of dawn. One is the dawn in which food becomes forbidden and prayer becomes permissible (the dawn prayer). The other is the one in which prayer (the dawn prayer) is forbidden and food (for suhur) is permissible. In Al-Mustadrak of Al-Hakim, it is stated that the (true dawn) in which food becomes forbidden is long on the horizon, and the other (false dawn) rises in the sky like the tail of a wolf. [صحيح ابن خذيمة، حديث 356۔ مستدرك حا كم : 191/1]

➋ Giving the call to prayer (adhan) before the time of prayer is not valid. However, if there is a slight mistake, there is no need to repeat the adhan. But if the interval is too long, the adhan should be repeated, and it should be announced regarding the first one that it was done by mistake. It should be noted that regarding the adhan of the dawn prayer, some of the scholars of hadith are inclined to the view that it should be given at the time of the false dawn, so that as soon as the true dawn appears, the prayer can be established and it can be performed in darkness. Their evidence is the hadith narrated from Abdullah bin Mas'ud radi Allahu anhu that the Prophet sallallahu alayhi wa sallam said: Let not the adhan of Bilal prevent you from eating suhur, for he gives the adhan at night, so that the one who is standing (in prayer) may be alerted and the one who is sleeping may wake up. [صحيح بخاري۔ الأذان باب الأذان قبل الفجر، حديث : 621]

Those who hold this view include Imam Malik, Awza'i, Shafi'i, Ahmad, and Ishaq. [خطابي]

However, the narration of Bukhari and Muslim clarifies the reality, as it is narrated from Aisha radi Allahu anha and Ibn Umar radi Allahu anhuma that the Prophet sallallahu alayhi wa sallam said: Bilal gives the adhan at night, so eat and drink until Ibn Umm Maktum gives the adhan. (And he was blind) and he would not give the adhan until it was said to him: "Morning has come, morning has come." [صحيح بخاري، حديث : 617۔ صحيح مسلم : حديث : 380۔ 381]

The purpose is that giving the adhan for the dawn prayer at the time of the actual appearance of dawn is the preferred (rajih) view.