Sahih Ibn Khuzaymah

In the narration of Yazid bin Aswad As-Suwa’i, it is mentioned that after performing the Fajr prayer, the Prophet Muhammad (peace be upon him) said to two men: “When you have performed the prayer at your residences and then you come (to the mosque) while the Imam is leading the prayer, then pray with him; it will become a voluntary (nafl) prayer for you. I will soon narrate this hadith in full detail, InshaAllah.” Imam Abu Bakr (may Allah have mercy on him) says that in this narration, the Prophet Muhammad (peace be upon him) commanded the person who had already performed the Fajr prayer at his residence to pray with the Imam. The Prophet (peace be upon him) stated that his prayer with the Imam would become nafl for him. Therefore, if the prohibition of praying after Fajr until sunrise was general and not specific, then it would not be permissible for the one who had already performed Fajr at his residence to perform the Fajr prayer again with the Imam as a nafl prayer. Also, the ahadith of the Prophet (peace be upon him) state that soon there will be rulers and leaders appointed over you who will delay the prayers from their prescribed times, so you should perform the prayer at its time and consider the prayer you perform with them as nafl. This is evidence that when the Imam delays the Asr or Fajr prayer, or both, it is obligatory for a person to perform both prayers at their prescribed times, then also perform them with the Imam, and consider the prayer performed with the Imam as nafl. And this will be a nafl prayer after Fajr and Asr. And previously, I have also written the hadith of Qais bin Qahd, which is of the same kind. And the Prophet Muhammad (peace be upon him) forbade Banu Abd Manaf and Banu Abdul Muttalib from preventing anyone from praying in the House of Allah at any hour of the day or night.