Sunan an-Nasa'i, Hadith 2145 ⓘ
It was narrated that 'Abdullah said: "Take Sahur." 'Ubaidullah said: "I do not know how he said it."
أَخْبَرَنَا عُبَيْدُ اللَّهِ بْنُ سَعِيدٍ، قَالَ حَدَّثَنَا عَبْدُ الرَّحْمَنِ، عَنْ أَبِي بَكْرِ بْنِ عَيَّاشٍ، عَنْ عَاصِمٍ، عَنْ زِرٍّ، عَنْ عَبْدِ اللَّهِ، قَالَ تَسَحَّرُوا . قَالَ عُبَيْدُ اللَّهِ لاَ أَدْرِي كَيْفَ لَفْظُهُ .
also referenced under: Book 22, Hadith 56 (In-Book) & Volume 3, Book 22, Hadith 2147 (DarusSalam)