Some people are in the habit of standing and looking on when they enter the masjid on the day of Jumu'ah while the Imaam has mounted the mimbar and the adhaan is on, they do that to avoid sitting down without the tahiyyatul-masjid while they repeat what the muadhin says.
This is wrong.
Listening to the Khutbah is waajib and repeating the statement of the muadhin is recommended.
Tha'labah bn Maalik said we met the era of Umar and Uthmaan, the practice was that whenever the Imaam came out on the day of Jumu'ah we would leave prayers, and when he begins to talk we would stop talking.'
The last part of the athar indicates that they used to talk when the Adhaan was on therefore the adhaan cannot prevent tahiyyatul-masjid.
Though if the Imaam is rounding off his speech and a person enters, the latter can wait for the iqaamah.
Allaah knows better.
See: Al Qawl Mubeen pp. 372-73.
In the past edition: