Sunan Ibn Majah, Volume 4, Book 25, Hadith 2968 (DarusSalam) ⓘ
It was narrated that Anas bin Malik said: “We went out with the Messenger of Allah to Makkah, and I heard him say: ‘Labbaika ‘Umratan wa hajjatan [Here I am (O Allah), for ‘Umrah and Hajj].’”
حَدَّثَنَا نَصْرُ بْنُ عَلِيٍّ الْجَهْضَمِيُّ، حَدَّثَنَا عَبْدُ الأَعْلَى بْنُ عَبْدِ الأَعْلَى، حَدَّثَنَا يَحْيَى بْنُ أَبِي إِسْحَاقَ، عَنْ أَنَسِ بْنِ مَالِكٍ، قَالَ خَرَجْنَا مَعَ رَسُولِ اللَّهِ ـ صلى الله عليه وسلم ـ إِلَى مَكَّةَ فَسَمِعْتُهُ يَقُولُ " لَبَّيْكَ عُمْرَةً وَحَجَّةً " .
also referenced under: Hadith 2968 (Reference) & Book 25, Hadith 3081 (In-Book)