question #1 Sahih Muslim 1240c, Book 15, Hadith 219 : What is the significance of pronouncing Talbiya during Hajj?

We went out with the Messenger of Allah (ﷺ) pronouncing Talbiya for Hajj, And in an the ahadith (narrated in this connection the words are): He led the morning prayer at al-Batha’, except al- jahdami who did not make mention of it.