question #1 Sahih Muslim 705f, Book 6, Hadith 66 : What is the significance of combining prayers in Islam?

Ibn ‘Abbas reported that the Messenger of Allah (ﷺ) observed in Medina seven (rak’ahs) and eight (rak’ahs), i. e. (be combined) the noon and afternoon prayers (eight rak’ahs) and the sunset and ‘Isha’ prayers (seven rak’ahs).