I asked Thabit al-Bunani whether it was permissible for a man to talk after the qamah had been pronounced. He narrated a tradition on the authority of Anas: (once) the Iqamah was pronounced, and a person came to the apostle of Allah (ﷺ) and detained him after the Iqamah had been pronounced.
Sunan Abi Dawud Book 2, Hadith 152
← Previous Hadith when the Iqamah was pronounced for prayer during the time of the Messenger of Allah (ﷺ), the people would take their seats before the prophet (ﷺ) came to his seat.

Sunan Abi Dawud Book 2, Hadith 151 Next Hadith → we stood for praying at Mina when the Imam had not come out. Some of us sat down (and I too). An old man from Kufah said to me: Why did you down? I said : Ibn Buraidah, this is Sumud (i.e., waiting for the Imam in the standing condition). The old man then narrated a tradition from ‘Abd al-Rahman b. ‘Awaajah on the authority of al-Bara’ b. ‘Azib: We would stand in rows during the time of the Messenger of Allah (ﷺ) for a long time before he pronounced Takbir. He further said; Allah, the Exalted and Mighty, sends blessings and the angles invoke blessings for those who are nearer to the front rows. No step is more liking to Allah than a step which one takes to join the row (of the prayer).

Sunan Abi Dawud Book 2, Hadith 153