The Prophet (ﷺ) commanded us to respond to the salutation of the imam. and to love each other, and to salute each other.
Sunan Abi Dawud Book 2, Hadith 612
← Previous Hadith The Messenger of Allah (ﷺ) entered upon us while the people were raising their hands. The narrator Zubair said: I think( they were raising the hands) during prayer. He (the prophet) said: What is the matter, I see you raising your hands as if they are the tails of restive horses! Maintain tranquility during prayer.

Sunan Abi Dawud Book 2, Hadith 611 Next Hadith → The end of the prayer of the Messenger of Allah (ﷺ) was known by the takbir (pronounced aloud).

Sunan Abi Dawud Book 2, Hadith 613