Sunan Ibn Majah, Volume 4, Book 25, Hadith 2969 (DarusSalam) ⓘ
It was narrated from Anas that the Prophet said: “Labbaika bi-‘Umratin wa hajjatin [Here I am (O Allah), for ‘Umrah and Hajj].”
حَدَّثَنَا نَصْرُ بْنُ عَلِيٍّ، حَدَّثَنَا عَبْدُ الْوَهَّابِ، حَدَّثَنَا حُمَيْدٌ، عَنْ أَنَسٍ، أَنَّ النَّبِيَّ ـ صلى الله عليه وسلم ـ قَالَ " لَبَّيْكَ بِعُمْرَةٍ وَحَجَّةٍ " .
also referenced under: Hadith 2969 (Reference) & Book 25, Hadith 3082 (In-Book)