Sayyiduna Anas (may Allah be pleased with him) narrates that I heard the Messenger of Allah (peace and blessings be upon him) saying: « لَبَّيْكَعُمْرَةًوَحَجًّا ، لَبَّيْكَعُمْرَةًوَحَجًّا » "O Allah, I am present for both ‘Umrah and Hajj. O Allah, I am present for both ‘Umrah and Hajj." He kept repeating these words.
Hadith Referenceصحيح ابن خزيمه / كتاب: المناسك / 2619