Answered by Shaykh Faraz Rabbani
I was wondering if u can pray the tahajjud prayer at the beginning of the time for fajr….when it is still dark?
1. The time for performing the night vigil (tahajjud) prayer ends when Isha time ends and Fajr time enters. Therefore, any voluntary prayers performed after Fajr time has entered does not count for the night vigil prayers.
2. After Fajr time enters, it is disliked to perform any voluntary prayers except the 2 rakats confirmed sunna of Fajr. This means that if one performed one’s sunna of Fajr at home, one does not perform the mosque greeting prayer (tahiyyat al-masjid); rather one simply sits down. [Ibn Abidin, Radd al-Muhtar; Shurunbulali, Maraqi al-Falah]
Imam Shurunbulali (Allah have mercy on him) explained in Maraqi al Falah that:
“It is offensive to perform nafl after the true dawn (beginning of Fajr time) more than the sunnah of Fajr, before performing the fard, because the Prophet (Allah bless him and give him peace) said, “the ones who are present should convey to those who are not present. Know! There is no salah after true dawn except two rakats [of the sunnah of Fajr].'” [Hashiya al Tahtawi ala Maraqi al Falah pg 151]
So, if one wants to perform the istikhara prayer after Fajr time has entered, one should intend it with one’s confirmed sunna, or wait until after sunrise.
3. This ruling was explained by Imam Burhan al-Din al-Marghinani in his Hidaya:
“(It is disliked to perform voluntary prayers after Fajr time enters, other than the two [confirmed sunna] rakats of Fajr.) This is because the Prophet (Allah bless him and give him peace) did not do more than this, despite his avidness to pray.”
Imam Kamal ibn al-Humam added in his Fath al-Qadir that:
Muslim related from Hafsa (Allah be pleased with her) that, “The Messenger of Allah (blessings and peace be upon him) did not pray anything other than two short rakats [i.e. of the confirmed sunna] after Fajr time entered.”
Abu Dawud and Tirmidhi relate from Ibn Umar (Allah be pleased with him) that the Prophet (Allah bless him and give him peace) said, “There is no [voluntary] prayer after Fajr except for two sets of prostrations.”‘ [Ibn al-Humam/Marghinani, Fath al-Qadir Sharh al-Hidaya, 1.239]