“Indeed, Allah showers His blessings upon the Prophet, and His angels pray for him. O believers! Invoke Allah's blessings upon him, and salute him with worthy greetings of peace.”
The salawat ayah (33:56) is quoted in the lecture on this event as continuing the same praise-of-the-Prophet ﷺ passage that opens with 33:37 (the marriage to Zaynab bint Jahsh RA) and includes 33:40 and 33:43.