Sunan Ibn Majah, Volume 1, Book 2, Hadith 691 (DarusSalam) ⓘ
It was narrated that Abu Hurairah said: "The Messenger of Allah said: 'Were it not that it would be too difficult for my Ummah, I would have delayed the 'Isha' prayer until one third or one half of the night had passed.'"
حَدَّثَنَا أَبُو بَكْرِ بْنُ أَبِي شَيْبَةَ، حَدَّثَنَا أَبُو أُسَامَةَ، وَعَبْدُ اللَّهِ بْنُ نُمَيْرٍ، عَنْ عُبَيْدِ اللَّهِ، عَنْ سَعِيدِ بْنِ أَبِي سَعِيدٍ، عَنْ أَبِي هُرَيْرَةَ، قَالَ قَالَ رَسُولُ اللَّهِ ـ صلى الله عليه وسلم ـ " لَوْلاَ أَنْ أَشُقَّ عَلَى أُمَّتِي لأَخَّرْتُ صَلاَةَ الْعِشَاءِ إِلَى ثُلُثِ اللَّيْلِ أَوْ نِصْفِ اللَّيْلِ " .
also referenced under: Hadith 691 (Reference) & Book 2, Hadith 25 (In-Book)