ENOfficial
‘A’isha said that the Prophet (ﷺ) was more particular about observing the two supererogatory rak'as at dawn than about observing any of the other supererogatory prayers. (Bukhari and Muslim.)
Source: sunnah.com
Other translations
Arabic
وَعَنْ عَائِشَةَ رَضِيَ اللَّهُ عَنْهَا قَالَتْ: لَمْ يَكُنِ النَّبِيُّ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ عَلَى شَيْءٍ مِنَ النَّوَافِلِ أَشَدَّ تَعَاهُدًا مِنْهُ على رَكْعَتي الْفجْر
sunnah.com