Sunan Ibn Majah, Book 5, Hadith 1198 (In-Book) ⓘ
It was narrated that Ibn ‘Umar said: “The Messenger of Allah used to pray two Rak’ah before the morning (prayer), as if the Adhan were in his ears. (i.e., he would pray them briefly).
حَدَّثَنَا أَحْمَدُ بْنُ عَبْدَةَ، أَنْبَأَنَا حَمَّادُ بْنُ زَيْدٍ، عَنْ أَنَسِ بْنِ سِيرِينَ، عَنِ ابْنِ عُمَرَ، قَالَ كَانَ رَسُولُ اللَّهِ ـ صلى الله عليه وسلم ـ يُصَلِّي الرَّكْعَتَيْنِ قَبْلَ الْغَدَاةِ كَأَنَّ الأَذَانَ بِأُذُنَيْهِ .
also referenced under: Hadith 1144 (Reference) & Volume 2, Book 5, Hadith 1144 (DarusSalam)