Sahih Muslim
The Book of Prayer - Travellers
كتاب صلاة المسافرين وقصرها
Chapter 13: It is recommended to pray Duha, the least of which is two rak`ah, the best of which is eight, and the average of which is four or six, and encouragement to do so regularly
اسْتِحْبَابِ صَلاَةِ الضُّحَى وَأَنَّ أَقَلَّهَا رَكْعَتَانِ وَأَكْمَلَهَا ثَمَانِ رَكَعَاتٍ وَأَوْسَطَهَا أَرْبَعُ رَكَعَاتٍ أَوْ سِتٌّ وَالْحَثِّ عَلَى الْمُحَافَظَةِ عَلَيْهَا
A hadith like this has been narrated by Qatada with the same chain of transmitters.
In the morning charity is due from every bone in the body of every one of you. Every utterance of Allah's glorification is an act of charity. Every utterance of praise of Him is an act of charity, every utterance of profession of His Oneness is an act of charity, every utterance of profession of His Greatness is an act of charity, enjoining good is an act of charity, forbidding what is distreputable is an act of charity, and two rak'ahs which one prays in the forenoon will suffice.
three fasts during every month, two rak'ahs of the forenoon prayer, and observing Witr prayer before going to bed.
A hadith like this has been narrated by Abu Huraira by another chain of transmitters.
My friend Abu'l-Qasim (ﷺ) instructed me to do three things, and the rest of the hadith is the same.
My Friend (ﷺ) instructed me in three (acts), and I would never abandon them as long as I live. (And these three things are): Three fasts during every month, the forenoon prayer, and this that I should not sleep till I have observed the Witr prayer.
Chapter 14: It is recommended to pray two rak`ah for the sunnah of Fajr. And encouragement to pray them regularly, and to make them brief, and to persist in offering them, and clarifying what is recommended to recite therein
اسْتِحْبَابِ رَكْعَتَيْ سُنَّةِ الْفَجْرِ وَالْحَثِّ عَلَيْهِمَا وَتَخْفِيفِهِمَا وَالْمُحَافَظَةِ عَلَيْهِمَا وَبَيَانِ مَا يُسْتَحَبُّ أَنْ يُقْرَأَ فِيهِمَا
Ibn 'Umar reported that Hafsa, the Mother of the Believers, informed him that when the Mu'adhdhin became silent after calling (people) to the dawn prayer, the Messenger of Allah (ﷺ) commenced the dawn (prayer) when it dawned by observing two short rak'ahs before the commencement of the (Fard) prayer.
This hadith has been transmitted by Nafi' with the same chain of narrators.
Hafsa reported that when it was dawn, the Messenger of Allah (ﷺ) did not observe (any other prayers) but two short rak'ahs.
A hadith like this has been narrated by Shu'ba with the same chain of transmitters.
When the dawn appeared, the Messenger of Allah (ﷺ) observed two rak'ahs (of Sunnah prayers).
The Messenger of Allah (ﷺ) used to observe two rak'ahs of Sunnah (prayer) when he heard the Adhin and shortened them.
" When it was dawn".
'A'isha reported that the Messenger of Allah (ﷺ) used to observe two (supererogatory) rak'ahs in between the call to prayer and the Iqama of the dawn prayer.
Did he recite in them Surah Fatiha (only)?
When it was dawn, the Messenger of Allah (ﷺ) observed two rak'ahs, and I would say: Does he recite only the opening chapter of the Qur'an in it?
'A'isha reported that the Apostle (ﷺ) was not so much particular about observing supererogatory rak'ahs as in case of the two rak'ahs of the dawn prayer.
I have never seen the Messenger of Allah (ﷺ) hastening as much in observing supererogatory as two rak'ahs before the (Fard) of the dawn prayer.
The two rak'ahs at dawn are better than this world and what it contains.
They are dearer to me than the whole world.