Which is better: performing the two Sunnah rak'ahs of Fajr and the two rak'ahs of Duha, or performing four rak'ahs for Duha prayer and not performing the Sunnah rak'ahs of Fajr, based on the hadith: "Perform for Me four rak'ahs at the beginning of the day, and I shall suffice you for its end"?

The Sunnah of Fajr is an emphasized Sunnah, and it is the best and most stressed of the regular Sunnah prayers, due to 'Aisha's saying: "The Prophet (peace be upon him) was not more diligent in performing any supererogatory prayers than he was in performing the two rak'ahs of Fajr." And due to his saying (peace be upon him): "Pray the two rak'ahs of Fajr even if horses are chasing you." As for the Dhuha prayer, its minimum is two rak'ahs, and the Hadith: "O son of Adam, do not fail to perform four rak'ahs for Me at the beginning of your day, and I will suffice you for the end of it," was interpreted by some scholars as referring to the obligatory Fajr prayer and its Sunnah.