Why was bowing (rukūʿ) specifically mentioned in the verse, "And bow down with those who bow down"?

The Almighty Allah's saying: "And establish prayer and give zakat and bow with those who bow" contains an order to perform prayer in congregation. The bowing mentioned here refers to the entire prayer. The reason for specifically mentioning bowing is either that it was more difficult for them than other actions, or to distinguish the prayer of Muslims from the prayer of the People of the Book, which does not include bowing.